mitochondrial mRNA editing complex

An mRNA editing complex found in the mitochondrion. The best characterized example is that of Trypanosoma brucei, which catalyzes the insertion and deletion of uridylates.

guiding stereospecific synthesis activity

The orientation of free radical substrates in such a way that only a particular stereoisomer is synthesized by an enzyme. Best characterized as a function during lignan biosynthesis.

COPII vesicle coat

One of two multimeric complexes that forms a membrane vesicle coat. COPII is best characterized in S. cerevisiae, where the subunits are called Sar1p, Sec13p, Sec31p, Sec23p, and Sec24p. Vesicles with COPII coats are found associated with endoplasmic reticulum (ER) membranes at steady state.

Holliday junction helicase complex

A DNA helicase complex found at Holliday junctions where the helicase activity is involved in the migration of the junction branch point. The best-characterized example is the E. coli RuvAB complex, in which a hexamer of RuvB subunits possesses helicase activity that is modulated by association with RuvA.

cyanelle ribonuclease P complex

A ribonuclease P complex located in the cyanelle, where it catalyzes the 5' endonucleolytic cleavage of precursor tRNAs to yield mature tRNAs. The best characterized cyanelle ribonuclease P complex, from the alga Cyanophora paradoxa, contains a single RNA molecule that is necessary but not sufficient for catalysis, and several protein molecules.

purine-rich negative regulatory element binding

Binding to a 30-bp purine-rich negative regulatory element; the best characterized such element is found in the first intronic region of the rat cardiac alpha-myosin heavy chain gene, and contains two palindromic high-affinity Ets-binding sites (CTTCCCTGGAAG). The presence of this element restricts expression of the gene containing it to cardiac myocytes.

SCF ubiquitin ligase complex

A ubiquitin ligase complex in which a cullin from the Cul1 subfamily and a RING domain protein form the catalytic core; substrate specificity is conferred by a Skp1 adaptor and an F-box protein. SCF complexes are involved in targeting proteins for degradation by the proteasome. The best characterized complexes are those from yeast and mammals (with core subunits named Cdc53/Cul1, Rbx1/Hrt1/Roc1).

nuclear SCF ubiquitin ligase complex

A ubiquitin ligase complex, located in the nucleus, in which a cullin from the Cul1 subfamily and a RING domain protein form the catalytic core; substrate specificity is conferred by a Skp1 adaptor and an F-box protein. SCF complexes are involved in targeting proteins for degradation by the proteasome. The best characterized complexes are those from yeast and mammals (with core subunits named Cdc53/Cul1, Rbx1/Hrt1/Roc1).

cytoplasmic SCF ubiquitin ligase complex

A ubiquitin ligase complex, located in the cytoplasm, in which a cullin from the Cul1 subfamily and a RING domain protein form the catalytic core; substrate specificity is conferred by a Skp1 adaptor and an F-box protein. SCF complexes are involved in targeting proteins for degradation by the proteasome. The best characterized complexes are those from yeast and mammals (with core subunits named Cdc53/Cul1, Rbx1/Hrt1/Roc1).

epsilon DNA polymerase complex

A heterotetrameric DNA polymerase complex that catalyzes processive DNA synthesis in the absence of PCNA, but is further stimulated in the presence of PCNA. The complex contains a large catalytic subunit and three small subunits, and is best characterized in Saccharomyces, in which the subunits are named Pol2p, Dpb2p, Dpb3p, and Dpb4p. Some evidence suggests that DNA polymerase epsilon is the leading strand polymerase; it is also involved in nucleotide-excision repair and mismatch repair.