CprK crystal structures reveal mechanism for transcriptional control of halorespiration.
Halorespiration is a bacterial respiratory process in which haloorganic compounds act as terminal electron acceptors. This process is controlled at transcriptional level by CprK, a member of the ubiquitous CRP-FNR family. Here we present the crystal structures of oxidized CprK in presence of the ligand ortho-chlorophenolacetic acid and of reduced CprK in absence of this ligand. These structures reveal that highly specific binding of chlorinated, rather than the corresponding non-chlorinated, phenolic compounds in the NH(2)-terminal beta-barrels causes reorientation of these domains with respect to the central alpha-helix at the dimer interface. Unexpectedly, the COOH-terminal DNA-binding domains dimerize in the non-DNA binding state. We postulate the ligand-induced conformational change allows formation of interdomain contacts that disrupt the DNA domain dimer interface and leads to repositioning of the helix-turn-helix motifs. These structures provide a structural framework for further studies on transcriptional control by CRP-FNR homologs in general and of halorespiration regulation by CprK in particular.
Joyce
M Gordon
MG
Manchester Interdisciplinary Biocentre, P. O. Box 88, Manchester, M60 1QD, United Kingdom.
Levy
Colin
C
Gábor
Krisztina
K
Pop
Stelian M
SM
Biehl
Benjamin D
BD
Doukov
Tzanko I
TI
Ryter
Jodi M
JM
Mazon
Hortense
H
Smidt
Hauke
H
van den Heuvel
Robert H H
RH
Ragsdale
Stephen W
SW
van der Oost
John
J
Leys
David
D
D001426:Bacterial Proteins / Q000737:chemistry*; D003460:Crystallization; D045858:Desulfitobacterium / Q000235:genetics* / Q000378:metabolism; D019281:Dimerization; D015964:Gene Expression Regulation, Bacterial; D010648:Phenylacetates / Q000378:metabolism; D017433:Protein Structure, Secondary; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D010648:Phenylacetates; C029718:3-chloro-4-hydroxyphenylacetic acid; C005756:2-hydroxyphenylacetic acid