Selenocysteine is the 21st proteinogenic amino acid. Selenoproteins contain selenocysteine residues. Selenocysteine is an analogue of the more common cysteine with selenium in place of the sulfur.
DNA primase is an enzyme involved in the replication of DNA and is a type of RNA polymerase. Primase catalyzes the synthesis of a short RNA segment called a primer complementary to a ssDNA template. After this elongation, the RNA piece is removed by a 5' to 3' exonuclease and refilled with DNA.
Pseudouridine is an isomer of the nucleoside uridine in which the uracil is attached via a carbon-carbon instead of a nitrogen-carbon glycosidic bond.
I-CreI is a homing endonuclease whose gene was first discovered in the chloroplast genome of Chlamydomonas reinhardtii, a species of unicellular green algae. It is named for the facts that: it resides in an Intron; it was isolated from Clamydomonas reinhardtii; it was the first (I) such gene isolated from C. reinhardtii. Its gene resides in a group I intron in the 23S ribosomal RNA gene of the C. reinhardtii chloroplast, and I-CreI is only expressed when its mRNA is spliced from the primary transcript of the 23S gene. I-CreI enzyme, which functions as a homodimer, recognizes a 22-nucleotide sequence of duplex DNA and cleaves one phosphodiester bond on each strand at specific positions. I-CreI is a member of the LAGLIDADG family of homing endonucleases, all of which have a conserved LAGLIDADG amino acid motif that contributes to their associative domains and active sites. When the I-CreI-containing intron encounters a 23S allele lacking the intron, I-CreI enzyme "homes" in on the "intron-minus" allele of 23S and effects its parent intron's insertion into the intron-minus allele. Introns with this behavior are called mobile introns. Because I-CreI provides for its own propagation while conferring no benefit on its host, it is an example of selfish DNA.
In enzymology and molecular biology, a holo-[acyl-carrier-protein] synthase is an enzyme that catalyzes the chemical reaction:
Morpheeins are proteins that can form two or more different homo-oligomers, but must come apart and change shape to convert between forms. The alternate shape may reassemble to a different oligomer. The shape of the subunit dictates which oligomer is formed. Each oligomer has a finite number of subunits (stoichiometry). Morpheeins can interconvert between forms under physiological conditions and can exist as an equilibrium of different oligomers. These oligomers are physiologically relevant and are not misfolded protein; this distinguishes morpheeins from prions and amyloid. The different oligomers have distinct functionality. Interconversion of morpheein forms can be a structural basis for allosteric regulation, an idea noted many years ago, and later revived. A mutation that shifts the normal equilibrium of morpheein forms can serve as the basis for a conformational disease. Features of morpheeins can be exploited for drug discovery. The dice image represents a morpheein equilibrium containing two different monomeric shapes that dictate assembly to a tetramer or a pentamer. The one protein that is established to function as a morpheein is porphobilinogen synthase, though there are suggestions throughout the literature that other proteins may function as morpheeins.
Helix 69 is a hairpin RNA structure containing 19 nucleotides in large subunit of the ribosome. Ribosome consists of large and small subunits joined with inter subunit bridges. Helix 69 interacts with the helix 44 (h44) of the small subunit to form the largest interface of two subunits called inter-subunit bridge B2a, one of the most conserved regions of the ribosome. Helix 69 is proposed to be a good drug target for antibacterial drugs. Many of the recent crystal structures have shown the involvement of this hairpin in different stages of the protein translation process. By targeting bacterial helix 69 specifically, protein synthesis in bacteria could be halted thus killing the bacteria.
16S rRNA (cytosine1407-C5)-methyltransferase (EC 2.1.1.178, RNA m5C methyltransferase YebU, RsmF, YebU) is an enzyme with systematic name S-adenosyl-L-methionine:16S rRNA (cytosine1407-C5)-methyltransferase. This enzyme catalyses the following chemical reaction
16S rRNA (adenine1518-N6/adenine1519-N6)-dimethyltransferase (EC 2.1.1.182, S-adenosylmethionine-6-N',N'-adenosyl (rRNA) dimethyltransferase, KsgA, ksgA methyltransferase) is an enzyme with systematic name S-adenosyl-L-methionine:16S rRNA (adenine1518-N6/adenine1519-N6)-dimethyltransferase. This enzyme catalyses the following chemical reaction
23S rRNA (guanine748-N1)-methyltransferase (EC 2.1.1.188, Rlma(II), Rlma2, 23S rRNA m1G748 methyltransferase, RlmaII, Rlma II, tylosin-resistance methyltransferase RlmA(II), TlrB, rRNA large subunit methyltransferase II) is an enzyme with systematic name S-adenosyl-L-methionine:23S rRNA (guanine748-N1)-methyltransferase. This enzyme catalyses the following chemical reaction
23S rRNA (cytosine1962-C5)-methyltransferase (EC 2.1.1.191, RlmI, rRNA large subunit methyltransferase I, YccW) is an enzyme with systematic name S-adenosyl-L-methionine:23S rRNA (cytosine1962-C5)-methyltransferase. This enzyme catalyses the following chemical reaction
Ribonuclease E is a bacterial ribonuclease that participates in the processing of ribosomal RNA and the chemical degradation of bulk cellular RNA.
23S rRNA pseudouridine2457 synthase is an enzyme with systematic name 23S rRNA-uridine2457 uracil mutase. This enzyme catalyses the following chemical reaction
23S rRNA pseudouridine2605 synthase is an enzyme with systematic name 23S rRNA-uridine2605 uracil mutase. This enzyme catalyses the following chemical reaction
23S rRNA pseudouridine1911/1915/1917 synthase (EC 5.4.99.23, RluD, pseudouridine synthase RluD) is an enzyme with systematic name 23S rRNA-uridine1911/1915/1917 uracil mutase. This enzyme catalyses the following chemical reaction
23S rRNA pseudouridine955/2504/2580 synthase is an enzyme with systematic name 23S rRNA-uridine955/2504/2580 uracil mutase. This enzyme catalyses the following chemical reaction
tRNA pseudouridine55 synthase is an enzyme with systematic name tRNA-uridine55 uracil mutase. This enzyme catalyses the following chemical reaction
tRNA pseudouridine13 synthase is an enzyme with systematic name tRNA-uridine13 uracil mutase. This enzyme catalyses the following chemical reaction
tRNA pseudouridine32 synthase is an enzyme with systematic name tRNA-uridine32 uracil mutase. This enzyme catalyses the following chemical reaction
23S rRNA pseudouridine746 synthase (EC 5.4.99.29, RluA, 23S RNA PSI746 synthase, 23S rRNA pseudouridine synthase, pseudouridine synthase RluA) is an enzyme with systematic name 23S rRNA-uridine746 uracil mutase. This enzyme catalyses the following chemical reaction
