Amide exchange rates in Escherichia coli acyl carrier protein: correlation with protein structure and dynamics. Protein Sci 1995 May;4(5):983-93
Date
05/01/1995Pubmed ID
7663354Pubmed Central ID
PMC2143121DOI
10.1002/pro.5560040518Scopus ID
2-s2.0-0028943591 (requires institutional sign-in at Scopus site) 67 CitationsAbstract
The acyl carrier protein (ACP) of Escherichia coli is a 77-amino acid, highly negatively charged three-helix protein that plays a central role in fatty acid biosynthesis. Previous NMR studies have suggested the presence of multiple conformations and marginally stable secondary structural elements. The stability of these elements is now examined by monitoring amide exchange in apo-ACP using NMR-based methods. Because ACP exhibits many rapid exchange rates, application of traditional isotope exchange methods is difficult. In one approach, heteronuclear correlation experiments with pulsed field-gradient coherence selection have reduced the time needed to collect two-dimensional 1H-15N correlation spectra to the point where measurement of exchange of amide protons for deuterium on the timescale of minutes can be made. In another approach, water proton selective inversion-exchange experiments were performed to estimate the exchange rates of protons exchanging on timescales of less than a second. Backbone amide protons in the region of helix II were found to exchange significantly more rapidly than those in helices I and III, consistent with earlier structural models suggesting a dynamic disruption of the second helix. Highly protected amides occur on faces of the helices that may pack into a hydrophobic core present in a partially disrupted state.
Author List
Andrec M, Hill RB, Prestegard JHMESH terms used to index this publication - Major topics in bold
Acyl Carrier ProteinAmides
Deuterium
Escherichia coli
Hydrogen
Kinetics
Magnetic Resonance Spectroscopy
Mathematics
Protein Conformation
Protein Structure, Secondary
