How do SorC proteins recognize their DNA operators?
M. Šoltysová1, J.
Škerlová1, P. Pachl1, J. Brynda1,2, I.
Sieglová1,2, M. Fábry2, M. Babiak3, J. Nováček3, P. Řezáčová1,2
1Institute of Organic
Chemistry and Biochemistry, CAS, v.v.i., Flemingovo nám. 2, 16610 Prague, Czech
Republic
2Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, Praha 4, 142 20, Czech Republic
3 Central European
Institute of Technology, Masaryk University, 62500 Brno, Czech Republic
rezacova@uochb.cas.cz
The SorC family is a large family of
bacterial transcription regulators involved in the control of carbohydrate
metabolism and quorum-sensing (1,2). SorC protomers constitute an N‑terminal helix‑turn‑helix DNA‑binding
domain (DBD) and a C‑terminal effector‑binding domain (EBD) that perceives a change in the environment by
binding a phosphor‑sugar molecule which affects oligomerization state and
subsequently the affinity to the DNA operator.
We have studied the mechanism of how these
proteins recognize their DNA and determined crystal structures of DBDs of two
representatives, bsCggR and bsDeoR from Bacillus subtilis
in complex with their DNA operators (3). In previous studies, EBDs of these two
proteins was also determined in their free form and in complex with their
effector molecules (4,5). Our
next question was how these proteins bind DNA in their full‑length forms
and what structural mechanism underlies the affinity change. To unveil this, we
have combined methods of X‑ray crystallography and cryogenic electron microscopy (cryo‑EM), thus completing the partial structural information about
separated EBDs and DBDs (3-5). To gain an overall picture of bsCggR
and bsDeoR in complex with their cognate DNA duplexes, we determined 4.5
Å cryo‑EM structure and 3.6 Å resolution crystal structure of bsCggR
and bsDeoR DNA complexes, respectively. These models represent the first
comprehensive insight into the DNA recognition by the SorC protein family.
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Bacillus subtilis reveal ligand-induced structural changes upon binding of
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