Premium
The DNA damage inducible protein UmuD inhibits replication
Author(s) -
Beuning Penny J,
Sefcikova Jana,
Fang Jing,
Engen John R,
Silva Michelle C
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.492.2
Subject(s) - sos response , dna clamp , dna damage , dna polymerase , dna replication , polymerase , dna , processivity , biology , dna repair , genetics , chemistry , microbiology and biotechnology , gene , biophysics , polymerase chain reaction , reverse transcriptase
All organisms experience DNA damage from a myriad of sources. When bacterial cells experience DNA damage, the SOS response is induced, leading to upregulation of at least 57 genes in E. coli . The SOS regulated genes include those involved in DNA repair and cell cycle regulation. Also induced as part of the SOS response are Y family DNA polymerases, which have the specialized ability to copy damaged DNA and tend to be error‐prone when replicating undamaged DNA. UmuD, a small manager protein, and its cleaved form, UmuD', directly interact with both Y family polymerases as well as the beta processivity clamp and the replicative DNA polymerase. We find that UmuD, but not UmuD′, inhibits primer extension by the DNA polymerase III alpha subunit. Thermal shift experiments show that UmuD undergoes two melting transitions, one likely due to the dissociation of the N‐terminal arms and the other due to unfolding of the globular domain. We used hydrogen‐deuterium exchange mass spectrometry (HXMS) to probe the conformations of UmuD and UmuD'. Our HXMS results reveal that the N‐terminal arm of UmuD is highly dynamic. Our observations are consistent with the proposed model of UmuD and the finding that UmuD is relatively unstructured. Research supported by NSF Career Award MCB‐0845033.