Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10748928 | Biochemical and Biophysical Research Communications | 2016 | 6 Pages |
Abstract
In Gram-positive Streptomyces coelicolor A3(2), SigR (Sc ÏR) of the group IV ECF sigma factor singly activates expression of more than 30 oxidation responsive genes. Of the two promoter-binding domains - individually called region 2 and region 4 - within Sc ÏR, we hereby report a 2.6Â Ã
resolution structure of the -35 element interacting carboxyl-terminal region 4 (Sc ÏR4). Structural comparison of Sc ÏR4 with the Escherichia coli SigE (Ec ÏE) in complex with Ec ÏE -35 element suggested that a single residue (Sc ÏR Met188 and Ec ÏE Arg171) may be responsible for distinguishing the one-base pair difference of the -35 elements - Sc ÏRâ31â²ATTCCâ35â² (â31â²A) vs. Ec ÏEâ31â²GTTCCâ35â² (â31â²G) - by interacting with the -31â²-base. Further studies using expressed Sc ÏR indicate that the wild-type Sc ÏR with Met188 selectively interacted with the â31â²A sequence over the â31â²G sequence, whereas a mutation of Met188 to arginine resulted in interaction with both â31â²A and â31â²G sequences. Hence, we conclude that Met188 of Sc ÏR confers the â31â²A-selectivity in -35 element interaction by disfavoured interaction with the â31â²G base.
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Authors
Keon Young Kim, Jeong Kuk Park, SangYoun Park,