DNA-directed RNA polymerase II subunit RPB4 (RNA polymerase II subunit B4) (DNA-directed RNA polymerase II subunit D) (RNA polymerase II 16 kDa subunit) (RPB16)
1_MAAGG 6_ SDPRA 11_ GDVEE 16_ DASQL 21_ IFPKE 26_ FETAE 31_ TLLNS 36_ EVHML 41_ LEHRK 46_ QQNES 51_ AEDEQ 56_ ELSEV 61_ FMKTL 66_ NYTAR 71_ FSRFK 76_ NRETI 81_ ASVRS 86_ LLLQK 91_ KLHKF 96_ ELACL 101_ ANLCP 106_ ETAEE 111_ SKALI 116_ PSLEG 121_ RFEDE 126_ ELQQI 131_ LDDIQ 136_TKRSF
1: Core component of RNA polymerase II (Pol II), a DNA-dependent RNA polymerase which synthesizes mRNA precursors and many functional non-coding RNAs using the four ribonucleoside triphosphates as substrates. Pol II is the central component of the basal RNA polymerase II transcription machinery. It is composed of mobile elements that move relative to each other. POLR2D/RPB4 is part of a subcomplex with POLR2G/RPB7 that binds to a pocket formed by POLR2A/RPB1, POLR2B/RPB2 and POLR2F/RPABC2 at the base of the clamp element. The POLR2D/RPB4-POLR2G/RPB7 subcomplex seems to lock the clamp via POLR2G/RPB7 in the closed conformation thus preventing double-stranded DNA to enter the active site cleft. The POLR2D/RPB4-POLR2G/RPB7 subcomplex binds single-stranded DNA and RNA