Crystallographic evidence of a large ligand-induced hinge-twist motion between the two domains of the maltodextrin binding protein involved in active transport and chemotaxis

Biochemistry. 1992 Nov 10;31(44):10657-63. doi: 10.1021/bi00159a003.

Abstract

The periplasmic maltodextrin binding protein of Escherichia coli serves as an initial receptor for the active transport of and chemotaxis toward maltooligosaccharides. The three-dimensional structure of the binding protein complexed with maltose has been previously reported [Spurlino, J. C., Lu, G.-Y., & Quiocho, F. A. (1991) J. Biol. Chem. 266, 5202-5219]. Here we report the structure of the unliganded form of the binding protein refined to 1.8-A resolution. This structure, combined with that for the liganded form, provides the first crystallographic evidence that a major ligand-induced conformational change occurs in a periplasmic binding protein. The unliganded structure shows a rigid-body "hinge-bending" between the two globular domains by approximately 35 degrees, relative to the maltose-bound structure, opening the sugar binding site groove located between the two domains. In addition, there is an 8 degrees twist of one domain relative to the other domain. The conformational changes observed between this structure and the maltose-bound structure are consistent with current models of maltose/maltodextrin transport and maltose chemotaxis and solidify a mechanism for receptor differentiation between the ligand-free and ligand-bound forms in signal transduction.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / metabolism
  • Biological Transport, Active
  • Carrier Proteins / chemistry*
  • Carrier Proteins / metabolism
  • Chemotaxis
  • Crystallization
  • Escherichia coli / chemistry*
  • Escherichia coli Proteins*
  • Models, Molecular
  • Molecular Sequence Data
  • Molecular Structure
  • Periplasmic Binding Proteins
  • Protein Conformation
  • X-Ray Diffraction

Substances

  • Bacterial Proteins
  • Carrier Proteins
  • Escherichia coli Proteins
  • MalE protein, E coli
  • Periplasmic Binding Proteins