Journal article
Conformational changes involving ammonia tunnel formation and allosteric control in GMP synthetase
Archives of biochemistry and biophysics, Vol.545, pp.22-32
03/01/2014
DOI: 10.1016/j.abb.2014.01.004
PMCID: PMC3954777
PMID: 24434004
Abstract
GMP synthetase is the glutamine amidotransferase that catalyzes the final step in the guanylate branch of de novo purine biosynthesis. Conformational changes are required to efficiently couple distal active sites in the protein; however, the nature of these changes has remained elusive. Structural information derived from both limited proteolysis and sedimentation velocity experiments support the hypothesis of nucleotide-induced loop- and domain-closure in the protein. These results were combined with information from sequence conservation and precedents from other glutamine amidotransferases to develop the first structural model of GMPS in a closed, active state. In analyzing this Catalytic model, an interdomain salt bridge was identified residing in the same location as seen in other triad glutamine amidotransferases. Using mutagenesis and kinetic analysis, the salt bridge between H186 and E383 was shown to function as a connection between the two active sites. Mutations at these residues uncoupled the two half-reactions of the enzyme. The chemical events of nucleotide binding initiate a series of conformational changes that culminate in the establishment of a tunnel for ammonia as well as an activated glutaminase catalytic site. The results of this study provide a clearer understanding of the allostery of GMPS, where, for the first time, key substrate binding and interdomain contacts are modeled and analyzed. (C) 2014 Elsevier Inc. All rights reserved.
Details
- Title: Subtitle
- Conformational changes involving ammonia tunnel formation and allosteric control in GMP synthetase
- Creators
- Justin C. Oliver - Purdue University West LafayetteRavidra Gudihal - Purdue University West LafayetteJohn W. Burgner - Purdue University West LafayetteAnthony M. Pedley - Purdue University West LafayetteAlexander T. Zwierko - University of CharlestonV. Jo Davisson - Purdue University West LafayetteRebecca S. Linger - University of Charleston
- Resource Type
- Journal article
- Publication Details
- Archives of biochemistry and biophysics, Vol.545, pp.22-32
- DOI
- 10.1016/j.abb.2014.01.004
- PMID
- 24434004
- PMCID
- PMC3954777
- NLM abbreviation
- Arch Biochem Biophys
- ISSN
- 0003-9861
- eISSN
- 1096-0384
- Publisher
- Elsevier
- Number of pages
- 11
- Grant note
- P20RR016477 / NATIONAL CENTER FOR RESEARCH RESOURCES; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA; NIH National Center for Research Resources (NCRR) NSF-IGERT 9987576 / National Science Foundation; National Science Foundation (NSF) T32GM008296 / NATIONAL INSTITUTE OF GENERAL MEDICAL SCIENCES; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA; NIH National Institute of General Medical Sciences (NIGMS) GM067195; P20RR016477; P20GM103434; T32GM008296 / National Institutes of Health; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA
- Language
- English
- Date published
- 03/01/2014
- Academic Unit
- Biochemistry and Molecular Biology
- Record Identifier
- 9984772259802771
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