1mpc
From Proteopedia
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MALTODEXTRIN-BINDING PROTEIN (MALTOSE-BINDING PROTEIN) MUTANT, WITH ARGININE REPLACING TRYPTOPHAN AT POSITION 230 (TRP-230-ARG)
Overview
A mutant of the periplasmic maltose-binding protein (MBP) with altered, transport properties was studied. A change of residue 230 from tryptophan, to arginine results in dominant-negative MBP: expression of this protein, against a wild-type background causes inhibition of maltose transport. As, part of an investigation of the mechanism of such inhibition, we have, solved crystal structures of both unliganded and liganded mutant protein., In the closed, liganded conformation, the side-chain of R230 projects into, a region of the surface of MBP that has been identified as important for, transport while in the open form, the same side-chain takes on a, different, and less ordered, conformation. The crystallographic work is, supplemented with a small-angle X-ray scattering study that provides, evidence that the solution conformation of unliganded mutant is similar to, that of wild-type MBP. It is concluded that dominant-negative inhibition, of maltose transport must result from the formation of a non-productive, complex between liganded-bound mutant MBP and wild-type MalFGK2. A general, kinetic framework for transport by either wild-type MalFGK2 or, MBP-independent MalFGK2 is used to understand the effects of, dominant-negative MBP molecules on both of these systems.
About this Structure
1MPC is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Crystal structures and solution conformations of a dominant-negative mutant of Escherichia coli maltose-binding protein., Shilton BH, Shuman HA, Mowbray SL, J Mol Biol. 1996 Nov 29;264(2):364-76. PMID:8951382
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