POLR2A CTD Heptapeptide Serine 5

**Semantic type:** Amino Acid, Peptide, or Protein

**Definition:** A serine that is the fifth residue of the heptapeptide repeat (YSPTSPS) in the C-terminal domain (CTD) of the largest RNA polymerase II subunit, DNA-directed RNA polymerase II subunit RPB1 (RPB1 or POLR2A). The RPB1 CTD is composed of up to 52 copies of this heptapeptide repeat and phosphorylation of serine-5 by the TFIIH subunit cyclin-dependent kinase 7 (CDK7) promotes RNA polymerase II-dependent transcriptional initiation and elongation.

**Synonyms:** - DNA-Directed RNA Polymerase II Subunit RPB1 C-Terminal Domain Heptapeptide Repeat Serine 5 - POL2RA CTD Ser5 - POLR2A CTD Heptapeptide Repeat Serine 5 - RNA Pol II CTD Ser5 - RNA Polymerase II Serine 5 - RNA Polymerase II Serine 5 - RNAIISer5 - RNAP2 CTD Ser5 - RPB1 CTD Heptapeptide Serine 5 - RPB1 CTD Ser5