U1 small nuclear ribonucleoprotein A (U1 snRNP A) (U1-A) (U1A)
1_MAVPE 6_ TRPNH 11_ TIYIN 16_ NLNEK 21_ IKKDE 26_ LKKSL 31_ YAIFS 36_ QFGQI 41_ LDILV 46_ SRSLK 51_ MRGQA 56_ FVIFK 61_ EVSSA 66_ TNALR 71_ SMQGF 76_ PFYDK 81_ PMRIQ 86_ YAKTD 91_ SDIIA 96_ KMKGT 101_ FVERD 106_ RKREK 111_ RKPKS 116_ QETPA 121_ TKKAV 126_ QGGGA 131_ TPVVG 136_ AVQGP 141_ VPGMP 146_ PMTQA 151_ PRIMH 156_ HMPGQ 161_ PPYMP 166_ PPGMI 171_ PPPGL 176_ APGQI 181_ PPGAM 186_ PPQQL 191_ MPGQM 196_ PPAQP 201_ LSENP 206_ PNHIL 211_ FLTNL 216_ PEETN 221_ ELMLS 226_ MLFNQ 231_ FPGFK 236_ EVRLV 241_ PGRHD 246_ IAFVE 251_ FDNEV 256_ QAGAA 261_ RDALQ 266_ GFKIT 271_ QNNAM 276_KISFA
1: Component of the spliceosomal U1 snRNP, which is essential for recognition of the pre-mRNA 5' splice-site and the subsequent assembly of the spliceosome. U1 snRNP is the first snRNP to interact with pre-mRNA. This interaction is required for the subsequent binding of U2 snRNP and the U4/U6/U5 tri-snRNP. SNRPA binds stem loop II of U1 snRNA. In a snRNP-free form (SF-A) may be involved in coupled pre-mRNA splicing and polyadenylation process. May bind preferentially to the 5'-UGCAC-3' motif on RNAs