PDBsum entry 1mpd

Periplasmic binding protein

PDB id: 1mpd

Contents

Protein chain

370 a.a. *

Ligands

GLC-GLC

Waters ×492

* Residue conservation analysis

PDB id:

1mpd

Name:

Periplasmic binding protein

Title:

Maltodextrin-binding protein (maltose-binding protein) mutant, with arginine replacing tryptophan at position 230 (trp-230-arg), complexed with maltose

Structure:

Maltodextrin-binding protein. Chain: a. Synonym: maltose-binding protein. Engineered: yes. Mutation: yes

Source:

Escherichia coli. Organism_taxid: 83333. Strain: k12. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.30Å R-factor: 0.168

Authors:

B.H.Shilton,S.L.Mowbray

Key ref:

B.H.Shilton et al. (1996). Crystal structures and solution conformations of a dominant-negative mutant of Escherichia coli maltose-binding protein. J Mol Biol, 264, 364-376. PubMed id: 8951382 DOI: 10.1006/jmbi.1996.0646

Date:

25-Jul-95 Release date: 15-Oct-95

Protein chain

P0AEX9  (MALE_ECOLI) -  Maltose/maltodextrin-binding periplasmic protein from Escherichia coli (strain K12)

Seq: 396 a.a.

Struc: 370 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1006/jmbi.1996.0646

J Mol Biol 264:364-376 (1996)

PubMed id: 8951382

Crystal structures and solution conformations of a dominant-negative mutant of Escherichia coli maltose-binding protein.

B.H.Shilton, H.A.Shuman, S.L.Mowbray.

ABSTRACT

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.

Selected figure(s)

Figure 2.
Figure 2. Location of dominant- negative and suppressor mutation sites on the structure of closed, ligand-bound MBP; maltose is shown in a ball and stick represen- tation. Other regions in which mutations are known that affect transport (Treptow & Shuman, 1988; Hor & Shuman, 1993) are indicated by the shaded areas.

Figure 3.
Figure 3. Stereo drawings of the backbone of open (a) and closed (b) MBPW230R. Every 20th amino acid is labelled, as well as the N and C termini. Bound maltose and the side-chain of R230 are shown with ball-and-stick representations. In the case of the open conformation, the view with respect to the C-ter- minal domain is the same as that shown in Figure 2. For closed MBPW230R, the view is the same as (b) that shown in Figure 2.

The above figures are reprinted by permission from Elsevier: J Mol Biol (1996, 264, 364-376) copyright 1996.

Figures were selected by an automated process.