Replication protein A, class 2b aminoacyl-tRNA synthetases, and related proteins with oligonucleotide/oligosaccharide (OB) fold.; This superfamily includes two oligonucleotide/oligosaccharide binding fold (OBF) domain families. One of these contains the OBF domains of the large (RPA1, 70kDa), middle (RPA2, RPA4, 32kDa) and small (RPA3, 14 kDa) subunits of human heterotrimeric Replication protein A (RPA), and similar domains. RPA is a nuclear single-strand (ss) DNA-binding protein involved in most aspects of DNA metabolism. This family includes the four OBF domains of RPA1 [DNA-binding domain (DBD)-A, DBD-B, DBD-C, and RPA1N], the OBF domain of RPA2 (RPA2 DBD-D), RPA3, and the OBF domain of RPA4. The major DNA binding activity of human RPA and Saccharomyces cerevisiae RPA appears to be associated with DBD-A and -B, of RPA1. RPA1 DBD-C shows only weak ssDNA-binding activity and is involved in trimerization. The other OBF domain family in this superfamily is the N-terminal, anticodon recognition domain of class 2b aminoacyl-tRNA synthetases (aaRSs). aaRSs catalyze the specific attachment of amino acids to their cognate tRNAs during protein biosynthesis. Class 2b aaRSs include the homodimeric aspartyl-, asparaginyl-, and lysyl-tRNA synthetases.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767967683   8 LLASVLALQNSSFIYPSCQKCFSRIILVSKRS-NCPKCGSTGEsgNANYRYKLSLKVAESNKLFVITVFGSCLDTFFGLT 86
Cdd:cd04476   20 VKATIVFIKPDNWWYPACPGCNKKVVEEGNGTyRCEKCNKSVP--NPEYRYILSLNVADHTGEAWLTLFDEVAEQIFGKS 97

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|....*
gi 767967683  87 ATGLHRYI-QDPNKIPETLDNDTtqnlltkavetcfvGQSFIFGV 130
Cdd:cd04476   98 AEELLELKeEDPDAFPDAIQDLV--------------GKTFLFRV 128

RPA1_DBD_C: A subfamily of OB folds corresponding to the C-terminal OB fold, the ssDNA-binding domain (DBD)-C, of human RPA1 (also called RPA70). RPA1 is the large subunit of Replication protein A (RPA). RPA is a nuclear ssDNA-binding protein (SSB) which appears to be involved in all aspects of DNA metabolism including replication, recombination, and repair. RPA also mediates specific interactions of various nuclear proteins. In animals, plants, and fungi, RPA is a heterotrimer with subunits of 70KDa (RPA1), 32kDa (RPA2), and 14 KDa (RPA3). In addition to DBD-C, RPA1 contains three other OB folds: DBD-A, DBD-B, and RPA1N. The major DNA binding activity of RPA is associated with RPA1 DBD-A and DBD-B. RPA1 DBD-C is involved in DNA binding and trimerization. It contains two structural insertions not found to date in other OB-folds: a zinc ribbon and a three-helix bundle. RPA1 DBD-C also contains a Cys4-type zinc-binding motif, which plays a role in the ssDNA binding function of this domain. It appears that zinc itself may not be required for ssDNA binding.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767967683   8 LLASVLALQNSSFIYPSCQKCFSRIILVSKRS-NCPKCGSTGEsgNANYRYKLSLKVAESNKLFVITVFGSCLDTFFGLT 86
Cdd:cd04476   20 VKATIVFIKPDNWWYPACPGCNKKVVEEGNGTyRCEKCNKSVP--NPEYRYILSLNVADHTGEAWLTLFDEVAEQIFGKS 97

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|....*
gi 767967683  87 ATGLHRYI-QDPNKIPETLDNDTtqnlltkavetcfvGQSFIFGV 130
Cdd:cd04476   98 AEELLELKeEDPDAFPDAIQDLV--------------GKTFLFRV 128

RPA1_DBD_C: A subfamily of OB folds corresponding to the C-terminal OB fold, the ssDNA-binding domain (DBD)-C, of human RPA1 (also called RPA70). RPA1 is the large subunit of Replication protein A (RPA). RPA is a nuclear ssDNA-binding protein (SSB) which appears to be involved in all aspects of DNA metabolism including replication, recombination, and repair. RPA also mediates specific interactions of various nuclear proteins. In animals, plants, and fungi, RPA is a heterotrimer with subunits of 70KDa (RPA1), 32kDa (RPA2), and 14 KDa (RPA3). In addition to DBD-C, RPA1 contains three other OB folds: DBD-A, DBD-B, and RPA1N. The major DNA binding activity of RPA is associated with RPA1 DBD-A and DBD-B. RPA1 DBD-C is involved in DNA binding and trimerization. It contains two structural insertions not found to date in other OB-folds: a zinc ribbon and a three-helix bundle. RPA1 DBD-C also contains a Cys4-type zinc-binding motif, which plays a role in the ssDNA binding function of this domain. It appears that zinc itself may not be required for ssDNA binding.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767967683   8 LLASVLALQNSSFIYPSCQKCFSRIILVSKRS-NCPKCGSTGEsgNANYRYKLSLKVAESNKLFVITVFGSCLDTFFGLT 86
Cdd:cd04476   20 VKATIVFIKPDNWWYPACPGCNKKVVEEGNGTyRCEKCNKSVP--NPEYRYILSLNVADHTGEAWLTLFDEVAEQIFGKS 97

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|....*
gi 767967683  87 ATGLHRYI-QDPNKIPETLDNDTtqnlltkavetcfvGQSFIFGV 130
Cdd:cd04476   98 AEELLELKeEDPDAFPDAIQDLV--------------GKTFLFRV 128