Structure of the Branched Chain Amino Acid and GTP Sensing Global Regulator, CodY, from Bacillus subtilis

TY - JOUR

T1 - Structure of the Branched Chain Amino Acid and GTP Sensing Global Regulator, CodY, from Bacillus subtilis

AU - Levdikov, Vladimir M

AU - Blagova, Elena V

AU - Young, Vicki L

AU - Belitsky, Boris R

AU - Lebedev, Andrey

AU - Sonenshein, Abraham L

AU - Wilkinson, Anthony J

N1 - Copyright 2016 by The American Society for Biochemistry and Molecular Biology, Inc. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details.

PY - 2016/12/23

Y1 - 2016/12/23

N2 - CodY is a branched-chain amino acid (BCAA) and GTP sensor, and a global regulator of transcription in low G + C Gram-positive bacteria. It controls the expression of over 100 genes and operons, principally by repressing during growth genes whose products are required for adaptations to nutrient limitation. CodY consists of a GAF domain that binds BCAAs and a winged helix-turn-helix (wHTH) domain that binds to DNA, but the way in which these domains interact and the structural basis of the BCAA-dependence of this interaction are unknown. To gain new insights, we determined the crystal structure of unliganded CodY from Bacillus subtilis revealing a 10-turn alpha-helix linking otherwise discrete GAF and wHTH domains. The structure of CodY in complex with isoleucine revealed a reorganised GAF domain. In both complexes CodY was tetrameric. Size exclusion chromatography with multiangle laser light scattering (SEC-MALLS) experiments showed that CodY is a dimer at concentrations found in bacterial cells. Comparison of structures of dimers of unliganded CodY and CodY-Ile derived from the tetramers showed a splaying of the wHTH domains when Ile was bound; splaying is likely to account for the increased affinity of Ile-bound CodY for DNA. Electrophoretic mobility shift and SEC-MALLS analyses of CodY binding to 19-36 base-pair operator fragment are consistent with isoleucine-dependent binding of two CodY dimers per duplex. The implications of these observations for effector control of CodY activity are discussed.

AB - CodY is a branched-chain amino acid (BCAA) and GTP sensor, and a global regulator of transcription in low G + C Gram-positive bacteria. It controls the expression of over 100 genes and operons, principally by repressing during growth genes whose products are required for adaptations to nutrient limitation. CodY consists of a GAF domain that binds BCAAs and a winged helix-turn-helix (wHTH) domain that binds to DNA, but the way in which these domains interact and the structural basis of the BCAA-dependence of this interaction are unknown. To gain new insights, we determined the crystal structure of unliganded CodY from Bacillus subtilis revealing a 10-turn alpha-helix linking otherwise discrete GAF and wHTH domains. The structure of CodY in complex with isoleucine revealed a reorganised GAF domain. In both complexes CodY was tetrameric. Size exclusion chromatography with multiangle laser light scattering (SEC-MALLS) experiments showed that CodY is a dimer at concentrations found in bacterial cells. Comparison of structures of dimers of unliganded CodY and CodY-Ile derived from the tetramers showed a splaying of the wHTH domains when Ile was bound; splaying is likely to account for the increased affinity of Ile-bound CodY for DNA. Electrophoretic mobility shift and SEC-MALLS analyses of CodY binding to 19-36 base-pair operator fragment are consistent with isoleucine-dependent binding of two CodY dimers per duplex. The implications of these observations for effector control of CodY activity are discussed.

U2 - 10.1074/jbc.M116.754309

DO - 10.1074/jbc.M116.754309

M3 - Article

C2 - 28011634

SN - 0021-9258

SP - 1

EP - 36

JO - The Journal of biological chemistry

JF - The Journal of biological chemistry

ER -