All articles starting with P

Protein secondary structure prediction

Protein secondary structure prediction assigns each amino acid in a sequence a structural label such as alpha helix, beta strand, or coil, with deep learning reaching 81–86% accuracy.

Protein sepa-1

Protein sepa-1 (SEPA-1, suppressor of ectopic P granule in autophagy mutants-1) is a C. elegans selective autophagy receptor that self-oligomerizes, binds PGL-3 and LGG-1, and mediates ubiquitin-independent degradation of P granule components in embryos.

Protein sequencing

Protein sequencing is the set of laboratory methods for determining the order of amino acids in a protein or peptide, dominated since the 1990s by mass spectrometry.

Protein SPO16 homolog

Protein SPO16 homolog (C1orf146, UniProt Q5VVC0) is a conserved meiosis-specific protein, the mammalian ortholog of yeast Spo16, that binds SHOC1 in an endonuclease-inactive XPF-ERCC1-like ZZS complex to stabilize recombination intermediates and promote crossovers; loss causes infertility in mice and humans.

Protein Stability

Protein stability describes how well a protein keeps its folded structure or activity under heat, chemical denaturants, pH shifts, or mechanical stress, a central quantity in protein engineering.

Protein staining

Protein staining is a bench technique using dyes or reagents to make proteins visible after separation in gels or on membranes, producing bands used for detection and quantification.

Protein structure

Protein structure, also known as protein conformation, is the three-dimensional organization of a protein molecule across four levels, from amino acid sequence to assembled multi-chain complexes, and it determines function.

Protein SUPPRESSOR OF GENE SILENCING 3

SGS3 (SUPPRESSOR OF GENE SILENCING 3, At5g23570) is a plant-specific RNA-binding protein that, with RDR6 in siRNA bodies, enables secondary siRNA and tasiRNA biogenesis, leaf development, and antiviral silencing, and is targeted by viral suppressors such as V2, p20, and AC4.

Protein synthesis inhibitor

Protein synthesis inhibitors are compounds, usually antibiotics or toxins, that block translation. Key classes target the 30S or 50S ribosomal subunit; first bacterial reports date to 1950, first eukaryotic report (cycloheximide) to 1958.

Protein tagging

Protein tagging is a bench biology method that attaches a detectable label to a protein of interest, either genetically or chemically, to report its location and interactions.

Protein tertiary structure

Protein tertiary structure: the full 3D fold of one polypeptide chain, stabilized mainly by the entropy-driven hydrophobic effect. Covers folding thermodynamics, Levinthal's paradox, chaperones, CATH/SCOP folds, X-ray/NMR/cryo-EM methods, AlphaFold2 accuracy, and misfolding diseases.

Oct 20, 2026

Protein trafficking Pga2

Pga2 (YNL149C) is an essential Saccharomyces cerevisiae protein involved in protein trafficking, required for maturation of Gas1p and Pho8p, localizing to the ER and nuclear envelope-ER network; distinct from prostaglandin A2.

Protein translocase complex, SecE/Sec61-gamma subunit

SecE/Sec61-gamma (SecE, Sss1p in yeast) is the small essential single-pass membrane subunit of the SecYEG/Sec61 protein-conducting channel, clamping the SecY/Sec61α pore, contacting the ribosome, and receiving the displaced plug during translocation.

Protein translocase subunit SecD

Protein translocase subunit SecD (gene secD, UniProt P0AG90) is an E. coli inner membrane protein that with SecF forms SecDF, a proton-motive-force-driven accessory complex of the SecYEG translocon completing ATP-independent protein export.

Protein translocase subunit SecY

SecY is the channel-forming core of SecYEG, the conserved bacterial and archaeal translocase that threads unfolded proteins across the cytoplasmic membrane, with SecA as its motor partner.

Protein Transport

Protein transport (protein trafficking, protein sorting): movement of proteins between cellular compartments via gated transport, transmembrane translocation, and vesicular transport, guided by sorting signals; Blobel's signal hypothesis won the 1999 Nobel Prize.

Protein transport protein Sec23

Sec23 (SEC23A/SEC23B in mammals) is the inner-coat COPII protein and Sar1 GAP that drives ER-to-Golgi vesicle transport; mutations cause CLSD and CDAII.

Oct 20, 2026

Protein transport protein Sec24

Sec24 (SEC24A–D in humans) is the cargo-selection subunit of the COPII coat, binding ER export signals to package proteins for ER-to-Golgi transport; four paralogs in A/B and C/D subgroups have overlapping but distinct cargo preferences.

Protein transport protein SEC31, conserved region

Sec31 (SEC31A, UniProt O94979) is the conserved outer-coat component of the COPII vesicle coat; its WD40 β-propeller, α-solenoid, and proline-rich domains build the Sec13/31 cage and stimulate Sar1 GTP hydrolysis in ER-to-Golgi transport.

Protein tyrosine phosphatase

Protein tyrosine phosphatases (PTPs, EC 3.1.3.48), enzymes dephosphorylating phosphotyrosine; over 100 human members, HC(X)5R motif, Cys215 nucleophile, two-step cysteinyl-phosphate mechanism, drug targets like PTP1B and SHP2.

Protein Unc-13

Protein unc-13 homolog A (Munc13-1, UNC13A) is a human presynaptic protein essential for synaptic vesicle priming via its MUN domain opening syntaxin-1; variants cause neurodevelopmental syndrome and modify ALS/FTD risk.

Protein Z600

Protein Z600 (Z600, frs, fruhstart, CG17962) is a 90-aa basic Drosophila melanogaster mitotic inhibitor that binds cyclin hydrophobic patches, delaying cycle 14 and mesoderm mitosis; ortholog GeneID 4812997 in D. pseudoobscura.

Oct 22, 2026

Protein-based self-assembling 2D materials

Protein-based self-assembling 2D materials are designed proteins that, when mixed, spontaneously form ordered, micrometre-scale two-dimensional lattices through engineered protein-protein interfaces, assembling both in solution and inside living cells.

Oct 20, 2026

Protein-export membrane protein SecF

SecF is the bacterial Sec-translocon accessory subunit that pairs with SecD as the SecDF complex, a 12-helix RND-superfamily membrane protein using the proton-motive force to pull preproteins from the SecYEG channel into the periplasm, independent of SecA ATPase.

Protein-fragment complementation assay

A protein-fragment complementation assay detects protein-protein interactions in living cells by splitting a reporter into inactive fragments that regain activity when the fused proteins interact, read out by fluorescence, luminescence, or survival.

Protein-L-histidine N-pros-methyltransferase

Protein-L-histidine N-pros-methyltransferase (METTL9, EC 2.1.1.B15) is a human seven-beta-strand SAM-dependent enzyme that installs 1-methylhistidine on the second His of HxH motifs in substrates such as S100A9, NDUFB3, and zinc transporters, producing most cellular 1-methylhistidine.

Protein-L-isoaspartate(D-aspartate) O-methyltransferase

Protein-L-isoaspartate(D-aspartate) O-methyltransferase, also called PIMT or PCMT (EC 2.1.1.77, human gene PCMT1), is a conserved ~24 kDa SAM-dependent repair enzyme that methylates spontaneous L-isoaspartyl and D-aspartyl damage in proteins; knockout mice die of epilepsy at about 42 days.

Protein-losing enteropathy

Protein-losing enteropathy (PLE), also called exudative enteropathy or Waldmann's disease when due to primary intestinal lymphangiectasia, is excessive loss of serum proteins into the gut, linked to over 60 conditions and diagnosed by α1-antitrypsin or 51Cr-albumin clearance.

Protein-sucrose

Protein-sucrose is a food ingredient of sucrose blended with food-grade protein, developed by the Israeli company Incredo to make sugar taste sweeter so less is needed.