#heterodimers

[tenth-sentence]

According to the model, tetramers composed of different homodimers and heterodimers of MADS domain proteins can exert combinatorial control over floral organ identity.

"Plant Physiology and Development" int'l 6e - Taiz, L., Zeiger, E., Møller, I.M., Murphy, A.

[whats-in-a-sentence]

These γ-tubulin ring complexes are present in the cortical cytoplasm, sometimes associated with the microtubule branches (Figure 1.26A-C), similar to how Arp 2/3 is present at branches of microfilaments. (...) Next, the protofilaments (the number varies with species) associate laterally to form a flat sheet (see Figure 1.26A). The sheet curls into a cylindrical microtubule as GTP is hydrolyzed (see Figure 1.26B). (...) The hydrolysis of GTP to GDP on the β-tubulin subunit causes the dimer to bend slightly, and if the rate of GTP hydrolysis "catches up" with the rate of addition of new heterodimers, the GTP-charged cap of tubulin vanishes and the protofilaments come apart from each other, initiating a catastrophic depolymerization that is much more rapid than the rate of polymerization (see Figure 1.26C). (...) This process is called dynamic instability (see Figure 1.26A-C).

However, plant microtubules can be released from γ-tubulin ring complexes by an ATPase, katanin (from the Japanese word katana, "samurai sword"), which severs the microtubule at the point where the growing microtubule branches off another (see Figure 1.26D). (...) During treadmilling, tubulin heterodimers are added to the growing plus end at about the same rate that they are removed from the shrinking minus end (see Figure 1.26D). The actual tubulin subunits do not move relative to the cell once they are polymerized into the microtubule (see shaded region in Figure 1.26D), because the microtubule is usually bound to a membrane through a variety of MAPs.

"Plant Physiology and Development" int'l 6e - Taiz, L., Zeiger, E., Møller, I.M., Murphy, A.

[materialsscienceandengineering]

Researchers realize controlled synthesis of Au-Ag heterodimer arrays for high-resolution encrypted information

Recently, a research group from Hefei Institutes of Physical Sciences of Chinese Academy of Sciences, developed an antielectric potential growth method for large-area preparation of Au-Ag heterodimer arrays. The prepared patterned Au-Ag dimer arrays have information resolution up to the nanometer scale due to the multipolar coupling resonance between the Au and Ag components. The research results were published in Nano Letters. The localized surface plasmonic resonance effects endow plasmonic nanoparticles (NPs) with the ability to modulate light-matter interactions, enabling patterned plasmonic arrays to encode complex colors and polarization patterns. Among them, the plasmonic heterogeneous arrays, which are composed of heterogeneous plasmonic NPs arranged periodically, have multi-dimensional optical tunability. It is conducive to the realization of high-resolution information encryption.

Read more.

[doforlove]

Literally screaming and crying and throwing up. They shouldnt make hot girls (me) learn immunology. What if this was me. U wouldnt make her learn about 5000 acronyms shes never heard of. She wouldnt have to know what a heterodimer of IL-1R1 and IL-1RAcP is. All she knows is live in tiny house and make tiny omlette. Everything is pain and hell on earth

[fungalmatingtypes]

Does any of this sound like the (dubious) human social/cultural constructs called “gender” to you?

Subtitle: How about you read about mating types in depth instead of passing around the same clickbait headline misinfo

Subtitle 2: remember at all times that what is true of sex in other species is not necessarily true of another, let alone comparing Homo sapiens to fungi (different kingdom)

Tetrapolar fungal mating types: sexes by the thousands

Erika Kothe

FEMS microbiology reviews 18 (1), 65-87, 1996

In order to achieve genetic rearrangement in a sexual cycle, eukaryotes go through the processes of meiosis and mating. Different mating types assure that mating is only possible between two genetically diverse individuals. Basidiomycetous fungi display thousands of different mating types that are determined by two genetically unlinked loci. One locus is multiallelic and contains genes for homeodomain transcription factors which are able to form heterodimers. The activation of target genes is dependent on heterodimers formed from the monomeric transcription factor proteins originating from different alleles of this genetic locus. The interactions between the two monomeric transcription factors and the activation of target genes by the heterodimeric proteins make this regulatory system both complex and interesting. The second locus contains a pheromone receptor system: the pheromone receptor is similar to the G protein-linked serpentine receptors in Saccharomyces cerevisiae that activate the pheromone response via a phosphorylation signal transduction cascade in S. cerevisiae. This pheromone perception is a trigger of sexual development and not, as with yeast, itself under control of mating type genes. Rather it directly senses diversity at the mating type loci. Whereas heterobasidiomycetes display a bi-allelic structure for this locus with recognition between one receptor and the opposite pheromone, homobasidiomycetes contain multiple specificities for pheromone receptors and pheromones.

—

Fungal sex: the Basidiomycota

Marco A Coelho, Guus Bakkeren, Sheng Sun, Michael E Hood, Tatiana Giraud

The fungal kingdom, 147-175, 2017

In the phylum Basidiomycota, a wide variety of lifestyles are represented. These range from well‐known and conspicuous wood‐decaying mushrooms, plant growth‐promoting and mutualistic mycorrhizae, and crop‐destroying smut and rust fungi, to yeast‐like human pathogens. Lifestyle differences have consequences for the mating and breeding systems of these fungi (see “Glossary,” below, for definitions of specialist terms used in this article), which are reflected in the genetic evolution of mating‐type determination. For over a century fungi have been recognized as having diverse breeding systems, from homothallism (i.e., universal compatibility among gametes, including among clonemates) to heterothallism (i.e., mating among haploid gametes carrying different mating‐type alleles). The study of breeding systems, for example, led to the discovery of the astounding variability in mating‐type alleles among mushrooms, with thousands of different mating types in some species (1), and to the realization that in many fungal pathogens the process of sexual reproduction is closely linked to infection and pathogenicity (2) (Fig. 1). The importance of basidiomycete fungi and their great research tractability, from ecology to genomics, have brought major insights into the diversification of genetic mechanisms used to achieve sexual reproduction.

—

Mating-Type Locus of Cryptococcus neoformans: a Step in the Evolution of Sex Chromosomes

Klaus B Lengeler, Deborah S Fox, James A Fraser, Andria Allen, Keri Forrester, Fred S Dietrich, Joseph Heitman

Eukaryotic Cell 1 (5), 704-718, 2002

The sexual development and virulence of the fungal pathogen Cryptococcus neoformans is controlled by a bipolar mating system determined by a single locus that exists in two alleles, α and a. The α and a mating-type alleles from two divergent varieties were cloned and sequenced. The C. neoformans mating-type locus is unique, spans >100 kb, and contains more than 20 genes. MAT-encoded products include homologs of regulators of sexual development in other fungi, pheromone and pheromone receptors, divergent components of a MAP kinase cascade, and other proteins with no obvious function in mating. The α and a alleles of the mating-type locus have extensively rearranged during evolution and strain divergence but are stable during genetic crosses and in the population. The C. neoformans mating-type locus is strikingly different from the other known fungal mating-type loci, sharing features with the self-incompatibility systems and sex chromosomes of algae, plants, and animals. Our study establishes a new paradigm for mating-type loci in fungi with implications for the evolution of cell identity and self/nonself recognition.

[moleculardepot]

Recombinant Human IL-27 Protein

Recombinant Human IL-27 Protein Catalog number: B2015886 Lot number: Batch Dependent Expiration Date: Batch dependent Amount: 5 ug Molecular Weight or Concentration: 25 and 30 kDa heterodimer, glycosylated Supplied as: Powder Applications: a molecular tool for various biochemical applications Storage: -20 °C Keywords: IL 27, IL 27 A, IL 27 subunit alpha, IL 27A, IL27, IL-27, IL27 A, IL27A,…

[jhavelikes]

The RGD (Arg-Gly-Asp)-binding integrins αvβ6 and αvβ8 are clinically validated cancer and fibrosis targets of considerable therapeutic importance. Compounds that can discriminate between the two closely related integrin proteins and other RGD integrins, stabilize specific conformational states, and have sufficient stability enabling tissue restricted administration could have considerable therapeutic utility. Existing small molecules and antibody inhibitors do not have all of these properties, and hence there is a need for new approaches. Here we describe a method for computationally designing hyperstable RGD-containing miniproteins that are highly selective for a single RGD integrin heterodimer and conformational state, and use this strategy to design inhibitors of αvβ6 and αvβ8 with high selectivity. The αvβ6 and αvβ8 inhibitors have picomolar affinities for their targets, and >1000-fold selectivity over other RGD integrins. CryoEM structures are within 0.6-0.7Å root-mean-square deviation (RMSD) to the computational design models; the designed αvβ6 inhibitor and native ligand stabilize the open conformation in contrast to the therapeutic anti-αvβ6 antibody BG00011 that stabilizes the bent-closed conformation and caused on-target toxicity in patients with lung fibrosis, and the αvβ8 inhibitor maintains the constitutively fixed extended-closed αvβ8 conformation. In a mouse model of bleomycin-induced lung fibrosis, the αvβ6 inhibitor potently reduced fibrotic burden and improved overall lung mechanics when delivered via oropharyngeal administration mimicking inhalation, demonstrating the therapeutic potential of de novo designed integrin binding proteins with high selectivity.

De novo design of highly selective miniprotein inhibitors of integrins αvβ6 and αvβ8 | bioRxiv

[kramlabs]

[actiasdara]

DNA Repair and Recombination

DNA Maintenance

DNA replication → inheritance

DNA repair → genome stability and integrity

DNA recombination → variety in organism

Why are DNA lesions lethal

Structural damage → prevent replication/transcription stalling of replication fork

Harmful mutations → impair survival of organism mutation in tumor suppressor gene (gene that prevent proliferation wildly, pro cell survival)

If unrepaired:

Senescence (cellular aging)

Apoptosis

Aberrant cell division cancer

Not all DNA lesions create cell death, but in some part they do

Culprits

Endogenous

Replication error

Reactive oxygen species

Defective repair system

Exogenous

Radiation

Interchelating agent

Carcinogen

Viruses (integrate genome to host)

Types of DNA Lesions

Single base changes

Damages on nucleobases or nucleotide

Examples:

Cytosine hydrolysis and become uracil (deamination)

Guanine methylation (add methyl group to guanine)

Guanine oxidation (may only create 2 hydrogen bond with C)

Depurination (lost of purin)

alkylation/methylation (protecting nucleotide)/oxidation

Repair:

Base excision repair

recognition of damage base and remove it (DNA glycosylase)

AP (area that don’t have nucleobase)

AP endonuclease (remove nucleotide of AP)

DNA Polymerase and ligase will fill the gap (divided into short and long “up to 10 nucleotides”)

Structural distortion

Bulky DNA lesions (include covalent bond “T dimer” triggered commonly by UV radiation)

Repair:

Nucleotide excision repair

Multicomplex nuclease (recognize and cut the bulky section)

DNA Helicase (the cut strand)

DNA polymerase and ligase (fill the gap)

DNA Mismatch

Repair

Mismatch excision repair

MutSalpha (MSH2-MSH6 heterodimer) recognize and recruit other protein

PCNA clamp, RFC, and Exo1 (cut the mismatch area)

Fill the gap

ligation

DNA backbone damage

Can occur when single strand break is not fixed

Strategies:

Homologous recombination (HR)

Active only in S-G2 phase

Require homologous chromosomes

Less efficient repair

Lead to faithful repair outcomes

Protein

MRN complex (cut and create ssDNA “overhang”)

Exo1 exonuclease (expose the overhang)

Rad51 Bind to 3’ ssDNA overhangs and help migrate

BRCA1 aids Rad51 search and invade homologous sequence

DNA polymerase

May end with crossover

Non-homologous end joining (NHEJ)

JUST JOIN THE END

Active throughout the cell cycle (last choice)

Could create small mutation (change DNA sequence, frame shift)

Ku protein (Ku70-Ku80), recognize and binds to DNA DSB ends

Protect and stabilize DNA ends

Recruit additional protein

Bring to ends together

Artemis (additional DNA end processing)

DNA-PK (kinase, add phosphate) and DNA ligase

Alternative End Joining

PARP1 → Recognize, binds, and match

Match with 2-20 nucleotide base pairing

PolQ (polymerase)

DNA Lesion Comes from Different Forms

Base pair mismatch (you get the idea, single base changes, most common)

Repair with mismatch repair

Single strand break (break of the phosphodiester bond on one strand, DNA backbone damage)

Single strand break repair

Structural base pair distortion (match with its own strand

Nucleotide excision repair (removal of entire nucleotide)

Nucleotide alteration (can change the helical structure)

Base excision repair

Double strand break

Homologous recombination

Non-homologous end joining

Genetic Recombination - Cross overs

Often happen in fertilization process

Morgan & Sturtevant

Types of Mutation

Silent mutation (mutation but same product, except when it create splicing region)

Missense mutation (produce different product, but same function)

Nonsense mutation (produce stop codon)

Frameshift (shift of translation frame)

Variation = Polymorphism

Single nucleotide polymorphism

Variation at single position in DNA sequence among individual

Single nucleotide variation

More than 1% of the population carries this sequence

Copy number variations

Variation in copy number of particular DNA sequence among individual

Structural Variation

[rnomics]

Nuclear SRP9/SRP14 heterodimer transcriptionally regulates 7SL and BC200 #RNA expression [Article]

The SRP9/SRP14 heterodimer is a central component of signal recognition particle (SRP) RNA (7SL) processing and Alu retrotransposition. In this study, we sought to establish the role of nuclear SRP9/SRP14 in the transcriptional regulation of 7SL and BC200 RNA. 7SL and BC200 RNA steady state levels, rate of decay, and transcriptional activity were evaluated under SRP9/SRP14 knockdown conditions. Immunofluorescent imaging, and subcellular fractionation of MCF-7 cells, revealed a distinct nuclear localization for SRP9/SRP14. The relationship between this localization and transcriptional activity at 7SL and BC200 genes was also examined. These findings demonstrate a novel nuclear function of SRP9/SRP14 establishing that this heterodimer transcriptionally regulates 7SL and BC200 RNA expression. We describe a model in which SRP9/SRP14 co-transcriptionally regulate 7SL and BC200 RNA expression. Our model is also a plausible pathway for regulating Alu RNA transcription and is consistent with the hypothesized roles of SRP9/SRP14 transporting 7SL RNA into the nucleolus for post-transcriptional processing, and trafficking of Alu RNA for retrotransposition. http://rnajournal.cshlp.org/cgi/content/short/rna.079649.123v1?rss=1&utm_source=dlvr.it&utm_medium=tumblr

[hivdoctorsindelhi]

Best HIV Human Immunodeficiency Virus Treatment

An explosion of knowledge in the fields of HIV Specialist Doctor in Delhi, pathogenesis (both immunologic and virologic), treatment of HIV disease, therapy and prophylaxis of HIV-associated opportunistic infections, and HIV prevention has coincided with the remarkable global spread of the HIV epidemic. Given the vast and expanding body of knowledge about HIV disease, it is essentially difficult for a general practitioner in healthcare to stay current with the most recent findings. This chapter's objective is to present the most recent data on the pandemic's scope, pathophysiology, treatment, and prevention, as well as its potential for vaccine development. Above all, the objective is to offer a solid scientific framework and practical therapeutic recommendations for an up-to-date strategy for HIV care.

The current CDC categorization system for HIV infection and AIDS groups patients according to their clinical HIV-related symptoms and CD4+ T lymphocyte counts. There are five stages of an established HIV infection (0, 1, 2, 3, or unknown). The stage is 0 and will stay that way for another 6 months if a negative HIV test was achieved within 6 months of the first HIV infection diagnosis. Advanced HIV disease (AIDS) is classified as stage 3 if one or more distinct opportunistic illnesses have been identified. Otherwise, the stage is determined by immunologic characteristics and the results of the CD4+ T lymphocyte test. The intricate and lengthy diagnostic and staging criteria for AIDS were created for surveillance rather than for actual patient management.

HIV MORPHOLOGY

According to electron microscopy, the HIV virion has an icosahedral form with numerous outside spikes made by the two main envelope proteins, external gp120 and transmembrane gp41. A trimeric heterodimer in three dimensions makes up the HIV envelope. After emerging off the surface of the infected cell, the virion creates a lipid bilayer that includes a variety of proteins from the host cell.

Precursors to HIV include:

• Headache.

• Fatigue.

• Muscle aches.

• A throat ache.

• Lymph node swelling.

• A red, non-itching rash that typically appears on your torso.

• Fever.

• Sores or ulcers in your genitalia, esophagus, mouth, or anus.

TRANSMISSION OF SEX

HIV infection is largely a sexually transmitted disease in the majority of the world (STI). Even while male-to-male sexual transmission is more common in many Western nations, heterosexual transmission is by far the most common way for an infection to spread, especially in developing nations. Although many factors, such as viral load and the frequency of ulcerative genital diseases, affect the effectiveness of heterosexual HIV transmission, such transmission is frequently inefficient. A recent systematic investigation revealed a low per-act likelihood of heterosexual transmission in the absence of antiretroviral therapy or condom use: 0.04 percent for female-to-male transmission and 0.08 percent for male-to-female transmission during vaginal intercourse. Seminal fluid from both infected and uninfected women has tested positive for HIV.

mononuclear cells and a material devoid of cells When lymphocytes and monocytes are in excess in the seminal fluid, as is the case with genital inflammatory illnesses such urethritis and epididymitis, which are strongly related to other STIs, the virus appears to concentrate there. The virus has been found in both vaginal fluid and cervical smears. Unprotected receptive anal intercourse (URAI) carries a higher risk of HIV transmission in both men and women than unprotected receptive vaginal intercourse (URVI). The per-act risk of HIV transmission via URAI has been estimated to be 1.4% despite the paucity of data. The risk of HIV acquisition associated with URAI is higher than that seen with penile-vaginal intercourse because only a thin, fragile rectal mucosal membrane separates the deposited semen from potentially susceptible cells in and beneath the mucosa, and micro-trauma of the mucosal membrane has been linked to anal intercourse.

Dr. Raina’s Safe Hands Clinic

Dr. Vinod Raina HIV Doctors in Greater Kailash

Contact Us-9136363692|9871605858

Address: — Saket E-34, Ekta Apartments near

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[whats-in-a-sentence]

Both receptors have three extracellular LysM domains that recognize Nod factors in a species-specific manner (Figure 23.2). (...) Nevertheless, the two proteins are thought to bind Nod factors in the heterodimeric state (see Figure 23.2).

"Plant Physiology and Development" int'l 6e - Taiz, L., Zeiger, E., Møller, I.M., Murphy, A.

[jhavelikes]

Relating the macroscopic properties of protein-based materials to their underlying component microstructure is an outstanding challenge. Here, we exploit computational design to specify the size, flexibility, and valency of de novo protein building blocks, as well as the interaction dynamics between them, to investigate how molecular parameters govern the macroscopic viscoelasticity of the resultant protein hydrogels. We construct gel systems from pairs of symmetric protein homo-oligomers, each comprising 2, 5, 24, or 120 individual protein components, that are crosslinked either physically or covalently into idealized step-growth biopolymer networks. Through rheological assessment and molecular dynamics (MD) simulation, we find that the covalent linkage of multifunctional precursors yields hydrogels whose viscoelasticity depends on the crosslink length between the constituent building blocks. In contrast, reversibly crosslinking the homo-oligomeric components with a computationally designed heterodimer results in non-Newtonian biomaterials exhibiting fluid-like properties under rest and low shear, but shear-stiffening solid-like behavior at higher frequencies. Exploiting the unique genetic encodability of these materials, we demonstrate the assembly of protein networks within living mammalian cells and show via fluorescence recovery after photobleaching (FRAP) that mechanical properties can be tuned intracellularly, in correlation with matching formulations formed extracellularly. We anticipate that the ability to modularly construct and systematically program the viscoelastic properties of designer protein-based materials could have broad utility in biomedicine, with applications in tissue engineering, therapeutic delivery, and synthetic biology.

De novo design of modular protein hydrogels with programmable intra- and extracellular viscoelasticity | bioRxiv

[royalvoxpost]

Tweeted

#StructuralBiology #Bioinformatics: scientists have devised a deep learning framework for predicting the inter-chain distance maps of both homodimers and heterodimers. The framework could help to determine the function of protein complexes - https://t.co/MAQnlBPI2Q https://t.co/Pkjt2W1cQZ

— The Royal Vox Post (@RoyalVoxPost) Nov 15, 2022

[whats-in-a-sentence]

The tubulin monomer of microtubules is a heterodimer composed of two similar polypeptide chains (α- and β-tubulin) (Figure 1.24A). (...) A microfilament is helical, a shape resulting from the polarity of association of the G-actin monomers (Figure 1.24B).

"Plant Physiology and Development" int'l 6e - Taiz, L., Zeiger, E., Møller, I.M., Murphy, A.