A novel signal transduction protein: Combination of solute binding and tandem PAS-like sensor domains in one polypeptide chain.
We report the structural and biochemical characterization of a novel periplasmic ligand-binding protein, Dret_0059, from Desulfohalobium retbaense DSM 5692, an organism isolated from Lake Retba, in Senegal. The structure of the protein consists of a unique combination of a periplasmic solute binding protein (SBP) domain at the N-terminal and a tandem PAS-like sensor domain at the C-terminal region. SBP domains are found ubiquitously, and their best known function is in solute transport across membranes. PAS-like sensor domains are commonly found in signal transduction proteins. These domains are widely observed as parts of many protein architectures and complexes but have not been observed previously within the same polypeptide chain. In the structure of Dret_0059, a ketoleucine moiety is bound to the SBP, whereas a cytosine molecule is bound in the distal PAS-like domain of the tandem PAS-like domain. Differential scanning flourimetry support the binding of ligands observed in the crystal structure. There is significant interaction between the SBP and tandem PAS-like domains, and it is possible that the binding of one ligand could have an effect on the binding of the other. We uncovered three other proteins with this structural architecture in the non-redundant sequence data base, and predict that they too bind the same substrates. The genomic context of this protein did not offer any clues for its function. We did not find any biological process in which the two observed ligands are coupled. The protein Dret_0059 could be involved in either signal transduction or solute transport.
Midwest Center for Structural Genomics, Argonne National Laboratory, Argonne, Illinois, 60439.|Biosciences Division, Argonne National Laboratory, Argonne, Illinois, 60439.
R
R
Wu
Biosciences Division, Argonne National Laboratory, Argonne, Illinois, 60439.
R
R
Wilton
Midwest Center for Structural Genomics, Argonne National Laboratory, Argonne, Illinois, 60439.|Biosciences Division, Argonne National Laboratory, Argonne, Illinois, 60439.|Structural Biology Center, Argonne National Laboratory, Argonne, Illinois, 60439.
M E
ME
Cuff
Midwest Center for Structural Genomics, Argonne National Laboratory, Argonne, Illinois, 60439.
M
M
Endres
Midwest Center for Structural Genomics, Argonne National Laboratory, Argonne, Illinois, 60439.|Biosciences Division, Argonne National Laboratory, Argonne, Illinois, 60439.
G
G
Babnigg
Mathematics and Computer Science Division, Argonne National Laboratory, Argonne, Illinois, 60439.|Computation Institute, University of Chicago, Chicago, Illinois, 60637.
J N
JN
Edirisinghe
Mathematics and Computer Science Division, Argonne National Laboratory, Argonne, Illinois, 60439.|Computation Institute, University of Chicago, Chicago, Illinois, 60637.
C S
CS
Henry
Midwest Center for Structural Genomics, Argonne National Laboratory, Argonne, Illinois, 60439.|Biosciences Division, Argonne National Laboratory, Argonne, Illinois, 60439.|Structural Biology Center, Argonne National Laboratory, Argonne, Illinois, 60439.|Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, 60637.
A
A
Joachimiak
Biosciences Division, Argonne National Laboratory, Argonne, Illinois, 60439.
M
M
Schiffer
Biosciences Division, Argonne National Laboratory, Argonne, Illinois, 60439.
P R
PR
Pokkuluri
D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020564:Deltaproteobacteria / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000072417:Protein Domains; D015398:Signal Transduction
D001426:Bacterial Proteins
cytosine; ketoleucine; ligand-binding protein; protein fold; structure