Purification and characterization of DnaC810, a primosomal protein capable of bypassing PriA function |
| |
Authors: | Xu L Marians K J |
| |
Institution: | Biochemistry and Structural Biology Graduate Program, Cornell University Graduate School of Medical Sciences, New York, New York 10021, USA. |
| |
Abstract: | Escherichia coli strains lacking PriA are severely compromised in their ability to repair UV-damaged DNA and to perform homologous recombination. These phenotypes arise because of a lack of PriA-directed replication fork assembly at recombination intermediates such as D-loops. Naturally arising suppressor mutations in dnaC restore strains carrying the priA2::kan null allele to wild-type function. We have cloned one such gene, dnaC810, and overexpressed, purified, and characterized the DnaC810 protein. DnaC810 can support a PriA-independent synthesis of phiX174 complementary strand DNA. This can be attributed to its ability, unlike wild-type DnaC, to catalyze a SSB-insensitive general priming reaction with DnaB and DnaG on any SSB-coated single-stranded DNA. Gel mobility shift analysis revealed that DnaC810 could load DnaB directly to SSB-coated single-stranded DNA as well as to D loop DNA. This explains the ability of DnaC810 to bypass the requirement for PriA, PriB, PriC, and DnaT during replication fork assembly at recombination intermediates. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|