CRYSTAL-STRUCTURE OF A POL ALPHA FAMILY REPLICATION DNA-POLYMERASE FROM BACTERIOPHAGE RB69

The 2.8 Angstrom resolution crystal structure of the bacteriophage RB6 9 gp43, a member of the eukaryotic pol alpha family of replicative DNA polymerases, shares some similarities with other polymerases but show s many differences. Although its palm domain has the same topology as other polymerases, except rat DNA polymerase beta, one of the three ca rboxylates required for nucleotidyl transfer is located on a different beta strand. The structures of the fingers and thumb domains are unre lated to all other known polymerase structures. The editing 3'-5' exon uclease domain of gp43 is homologous to that of E. coli DNA polymerase I but lies on the opposite side of the polymerase active site. An ext ended structure-based alignment of eukaryotic DNA polymerase sequences provides structural insights that should be applicable to most eukary otic DNA polymerases.