The Dynamics of the Mgatp-driven Closure of Malk, the Energy-transducing Subunit of the Maltose Abc Transporter.
From: Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
The Journal of biological chemistry
- Publish Date: Sep 2006
- ISSN: 0021-9258
- Volume: 281
- Issue: 38
- Pages: 28397-407
- Medium: Print
- Language: English
- Citation (JAMA): Oloo Eliud O, Fung Eric Y, Tieleman D Peter, et al. The Dynamics of the Mgatp-driven Closure of Malk, the Energy-transducing Subunit of the Maltose Abc Transporter.. J. Biol. Chem. Sep 2006;281:28397-407
Abstract
The nucleotide binding domains (NBDs) are the energy supplying subunits of ATP-binding cassette (ABC) proteins. They power transport by binding and hydrolyzing ATP. Tracing the pathway between different conformational states of the NBDs during ATP binding, hydrolysis, and release has, however, proven difficult. We have used molecular dynamics simulations to study the ATP-driven association of the NBDs of the maltose ABC transporter, MalK, based on the crystal structures of its open and semiopen dimers. When MgATP was introduced into the binding pockets, the semiopen dimer transitioned to a closed conformation, whereas the open dimer evolved to a semiopen state. In the absence of docked MgATP, however, the twin NBDs of both the open and semiopen starting configurations drifted further apart. Both the presence of MgATP and direct cross-interface protein-protein hydrogen bonds, primarily involving the D-loop, quite likely play a key role in initiating closure. The simulations of the MgATP-docked semiopen form indicate that completion of closure is driven mainly by cross-interface contacts between the gamma-phosphate of ATP and residues in the signature motif. Our simulations also give insight into possible interactions of MalK with the regulatory proteins MalT and enzyme IIA(glc).
Mesh Headings (Keywords): ATP-Binding Cassette Transporters, Adenosine Triphosphate, Binding Sites, Crystallization, DNA-Binding Proteins, Dimerization, Escherichia coli Proteins, Magnesium, Protein Conformation, Protein Subunits, Transcription Factors
Check for Full Text / PubMed Unique Identifier (PMID): 16877382
This abstract is part of PubMed, a service of the U.S. National Library of Medicine. PubMed includes more than 17 million citations from MEDLINE and other life science journals for biomedical articles. See Copyright and Disclaimers.
Linked medical terms appearing on this page are added by Healia to help readers find more information and are not part of the original PubMed document.
The data herein was last updated on July 8th, 2008 and may not reflect the most current and accurate data available from NLM.