All articles starting with R
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Ribose
Ribose (D-ribose) is an aldopentose sugar, C5H10O5, forming the RNA backbone; deoxyribose serves DNA. Made as ribose 5-phosphate via the pentose phosphate pathway; also studied in prebiotic chemistry and sold as a supplement.
Ribose 5-phosphate
Ribose 5-phosphate (R5P), a phosphorylated five-carbon sugar made from glucose-6-phosphate by the pentose phosphate pathway, is the precursor for PRPP and nucleotide synthesis and a metabolic checkpoint in cancer cells.
Ribose 5-phosphate isomerase, type A
Ribose 5-phosphate isomerase type A (RpiA, RPIA, EC 5.3.1.6) is the widespread isoform of the enzyme interconverting ribose-5-phosphate and ribulose-5-phosphate in the pentose phosphate pathway and Calvin cycle, distinct from the unrelated RpiB.
Ribose-5-phosphate isomerase
Ribose-5-phosphate isomerase (Rpi, EC 5.3.1.6) interconverts ribose 5-phosphate and ribulose 5-phosphate in the pentose phosphate pathway and Calvin cycle. Two unrelated forms, RpiA and RpiB, catalyze the reaction; RpiB is a drug target and rare-sugar biocatalyst.
Ribose-5-phosphate isomerase deficiency
Ribose-5-phosphate isomerase deficiency (RPI deficiency, RPIA, OMIM 608611) is an extremely rare autosomal recessive pentose phosphate pathway disorder causing progressive leukoencephalopathy, epilepsy, ataxia, and elevated ribitol and D-arabitol, with only a handful of diagnosed patients.
Ribosomal biogenesis factor
RBIS (ribosomal biogenesis factor, UniProt Q8N0T1) is a human chromosome 8 protein, a vertebrate-specific trans-acting factor required for efficient 40S and 60S ribosomal subunit production, containing the DUF4665 domain and interacting with GNL2 in lung adenocarcinoma progression.
Ribosomal DNA repeat array
A ribosomal DNA repeat array is a tandem cluster of rRNA genes; in humans the arrays sit on five acrocentric chromosomes and form the nucleolar organizer regions.
Ribosomal DNA sequencing
Ribosomal DNA sequencing amplifies and sequences ribosomal RNA gene regions, most often the bacterial 16S rRNA gene or the fungal ITS, to identify and classify the organisms in a sample.
Ribosomal protein
Ribosomal proteins are the protein components of ribosomes, also called r-proteins: 57 in bacteria, 68 in archaea, 78 in eukaryotes. They stabilize the rRNA core, bind RNA via motifs like OB fold and RNP, and assemble subunits.
Ribosomal protein L11 methyltransferase
Ribosomal protein L11-methyltransferase (PrmA, EC 2.1.1) is a bacterial S-adenosylmethionine-dependent enzyme that trimethylates amino groups of ribosomal protein L11, a conserved component of the large ribosomal subunit.
Ribosomal protein mS81
Ribosomal protein mS81, also called rPPR8 (Arabidopsis AT5G15980, UniProt Q8LPF1), is a pentatricopeptide repeat protein of the mitochondrial small ribosomal subunit head extension in plants, with a 355-residue counterpart in Tetrahymena.
Ribosomal protein mS82
Ribosomal protein mS82 is a mitochondrial mitoribosomal protein named under the unified nomenclature; in plants encoded by Arabidopsis AT4G22000 (tyrosine sulfotransferase-like), actually a large-subunit protein pending renaming, with no bacterial, yeast, or mammalian homologs.
Ribosomal protein S23-like
Ribosomal protein S23-like (InterPro IPR059199) is the protein family covering small-subunit ribosomal protein S12/S23 (uS12), a decoding-center component; distinct from mitochondrial mS23 (MRPS23).
Ribosomal RNA
Ribosomal RNA (rRNA), including 16S, 23S, 5S, 18S, 28S, and 5.8S forms, is the most abundant cellular RNA and the structural and catalytic core of ribosomes, catalyzing peptide bond formation and serving as the target of most antibiotics.
Ribosomal RNA adenine dimethylase
Ribosomal RNA adenine dimethylase (KsgA, Dim1, RsmA): universally conserved methyltransferase dimethylating A1518/A1519 of 16S rRNA helix 45; ksgA loss causes kasugamycin resistance; eukaryotic Dim1 essential for pre-18S rRNA processing.
Ribosomal RNA large subunit methyltransferase F
RlmF (YbiN, rlmF, EC 2.1.1.181) is the E. coli SAM-dependent methyltransferase that converts adenine 1618 of 23S rRNA to m6A, acting on partially deproteinized 50S assembly intermediates; its knockout slows growth.
Ribosomal RNA large subunit methyltransferase M
RlmM (YgdE, EC 2.1.1.186), ribosomal RNA large subunit methyltransferase M of E. coli; AdoMet-dependent 2′O methyltransferase making Cm2498 in 23S rRNA; THUMP plus Rossmann-fold MTase; acts early in 50S assembly.
Ribosomal RNA Methyltransferase
Ribosomal RNA methyltransferases are SAM-dependent enzymes that methylate rRNA bases or 2′-OH groups; class I Rossmann-fold and class IV SPOUT enzymes predominate, and bacterial variants such as Cfr confer multi-class antibiotic resistance.
Ribosomal s6 kinase
Ribosomal S6 kinase (RSK, MAPKAP-K1, RPS6KA1/2/3/6): a family of four ERK-activated dual-kinase-domain serine/threonine kinases phosphorylating rpS6 Ser235/236, CREB, and BAD; RSK2 mutations cause Coffin–Lowry syndrome.
Ribosome
A ribosome is the macromolecular machine in all living cells that translates messenger RNA into protein, built from ribosomal RNA and proteins in two subunits, and is a main target of antibiotics.
Ribosome assembly and maturation factors
Ribosome assembly and maturation factors are non-ribosomal proteins that chaperone, remodel, and proofread ribosomal subunits, with about 50 acting in bacteria and over 200 in eukaryotes.
Ribosome biogenesis
Ribosome biogenesis: synthesis and assembly of ribosomes. In eukaryotes it spans nucleolus, nucleoplasm, and cytoplasm, uses over 200 assembly factors, starts with Pol I-transcribed pre-rRNA forming 90S pre-ribosomes that yield 40S and 60S subunits; in prokaryotes it is cotranscriptional and compartment-free.
Ribosome biogenesis methyltransferase NEP1, archaea
Archaeal Nep1 (Emg1) is a dimeric SPOUT-class SAM-dependent methyltransferase that N1-methylates pseudouridine in helix 35 of archaeal 16S rRNA and aids ribosome assembly; it is distinct from TrmY, the archaeal tRNA m1Ψ54 enzyme.
Ribosome biogenesis protein Alb1
Alb1 (ALB1, UniProt P47019) is a 175-amino-acid yeast nuclear shuttling factor in 60S ribosomal subunit biogenesis; it partners with Arx1, escorts pre-60S particles to the cytoplasm, and is released by the AAA-ATPase Drg1, distinct from Arabidopsis ALBINA 1.
Ribosome profiling
Ribosome profiling (Ribo-seq) is a deep-sequencing method measuring genome-wide translation by sequencing ~30-nucleotide ribosome-protected mRNA fragments, introduced in 2009, enabling codon-level ribosome positions, translation efficiency, and novel ORF discovery.
Ribosome recycling factor
Ribosome recycling factor (RRF), bacterial protein encoded by frr, works with EF-G and GTP hydrolysis to split post-termination 70S ribosomes into subunits; essential in prokaryotes, absent in eukaryotes, which use ABCE1.
Ribosome rescue and quality control
Ribosome rescue and quality control are the systems that free ribosomes stalled on mRNAs lacking stop codons or damaged, then degrade the incomplete proteins, via tmRNA in bacteria and Pelota in eukaryotes.
Ribosome shunting
Ribosome shunting: a cap-dependent eukaryotic translation initiation mode where the 40S subunit bypasses structured 5' leader regions between donor and acceptor motifs; first described in cauliflower mosaic virus, also used by adenovirus, RTBV, Sendai virus, and Hsp70 mRNA.
Ribosome-associated endoribonuclease 1
Ribosome-associated endoribonuclease 1 (Rae1, formerly YacP) is a 19.5 kDa NYN/PIN endoribonuclease from Bacillus subtilis that cleaves mRNAs only during translation, 12 nt upstream of stop codons or stalling motifs at paused ribosomes.
Ribosome-inactivating protein
Ribosome-inactivating proteins (RIPs), including ricin and abrin, are plant N-glycosidases (EC 3.2.2.22) that depurinate 28S rRNA's sarcin-ricin loop, halting protein synthesis; type 1 are single-chain and low-toxicity, type 2 carry a lectin B-chain.