Document Detail


Bridging the gap between chemistry, physiology, and evolution: Quantifying the functionality of sperm whale myoglobin mutants.
MedLine Citation:
PMID:  21903173     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
This work merges a large set of previously reported thermochemical data for myoglobin (Mb) mutants with a physiological model of O(2)-transport and -storage. The model allows a quantification of the functional proficiency of myoglobin (Mb) mutants under various physiological conditions, i.e. O(2)-consumption rate resembling workload, O(2) partial pressure resembling hypoxic stress, muscle cell size, and Mb concentration, resembling different organism-specific and compensatory variables. We find that O(2)-storage and -transport are distinct functions that rank mutants and wild type differently depending on O(2) partial pressure. Specifically, the wild type is near-optimal for storage at all conditions, but for transport only at severely hypoxic conditions. At normoxic conditions, low-affinity mutants are in fact better O(2)-transporters because they still have empty sites for O(2), giving rise to a larger [MbO(2)] gradient (more varying saturation curve). The distributions of functionality reveal that many mutants are near-neutral with respect to function, whereas only a few are strongly affected, and the variation in functionality increases dramatically at lower O(2) pressure. These results together show that conserved residues in wild type (WT) Mb were fixated under a selection pressure of low P(O2).
Authors:
Pouria Dasmeh; Kasper P Kepp
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-8-8
Journal Detail:
Title:  Comparative biochemistry and physiology. Part A, Molecular & integrative physiology     Volume:  -     ISSN:  1531-4332     ISO Abbreviation:  -     Publication Date:  2011 Aug 
Date Detail:
Created Date:  2011-9-9     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9806096     Medline TA:  Comp Biochem Physiol A Mol Integr Physiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2011. Published by Elsevier Inc.
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