PMID:17825319

Citation	Xu, X, Wang, S, Hu, YX and McKay, DB (2007) The periplasmic bacterial molecular chaperone SurA adapts its structure to bind peptides in different conformations to assert a sequence preference for aromatic residues. J. Mol. Biol. 373:367-81
Abstract	The periplasmic molecular chaperone protein SurA facilitates correct folding and maturation of outer membrane proteins in Gram-negative bacteria. It preferentially binds peptides that have a high fraction of aromatic amino acids. Phage display selections, isothermal titration calorimetry and crystallographic structure determination have been used to elucidate the basis of the binding specificity. The peptide recognition is imparted by the first peptidyl-prolyl isomerase (PPIase) domain of SurA. Crystal structures of complexes between peptides of sequence WEYIPNV and NFTLKFWDIFRK with the first PPIase domain of the Escherichia coli SurA protein at 1.3 A resolution, and of a complex between the dodecapeptide and a SurA fragment lacking the second PPIase domain at 3.4 A resolution, have been solved. SurA binds as a monomer to the heptapeptide in an extended conformation. It binds as a dimer to the dodecapeptide in an alpha-helical conformation, predicated on a substantial structural rearrangement of the SurA protein. In both cases, side-chains of aromatic residues of the peptides contribute a large fraction of the binding interactions. SurA therefore asserts a recognition preference for aromatic amino acids in a variety of sequence configurations by adopting alternative tertiary and quaternary structures to bind peptides in different conformations.
Links	PubMed PMC2040117 Online version:10.1016/j.jmb.2007.07.069
Keywords	Amino Acid Sequence; Binding Sites; Carrier Proteins/chemistry; Carrier Proteins/genetics; Carrier Proteins/metabolism; Crystallography, X-Ray; Escherichia coli Proteins/chemistry; Escherichia coli Proteins/genetics; Escherichia coli Proteins/metabolism; Models, Molecular; Molecular Chaperones/chemistry; Molecular Chaperones/metabolism; Molecular Sequence Data; Mutagenesis, Site-Directed; Peptides/chemistry; Peptides/metabolism; Peptidylprolyl Isomerase/chemistry; Peptidylprolyl Isomerase/genetics; Peptidylprolyl Isomerase/metabolism; Periplasm/metabolism; Protein Conformation; Protein Folding; Structure-Activity Relationship; Substrate Specificity
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
ECOLI:SURA	enables	GO:0042277: peptide binding	ECO:0000314: direct assay evidence used in manual assertion		F		Seeded From UniProt	complete

References

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