Bridging the gap between chemistry, physiology, and evolution: Quantifying the functionality of sperm whale myoglobin mutants

Publication: Research - peer-reviewJournal article – Annual report year: 2011

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@article{657df0a5fb2b4470b0b7dfc1a82a508b,
title = "Bridging the gap between chemistry, physiology, and evolution: Quantifying the functionality of sperm whale myoglobin mutants",
publisher = "Elsevier Inc.",
author = "Pouria Dasmeh and Kepp, {Kasper Planeta}",
year = "2011",
doi = "10.1016/j.cbpa.2011.07.027",
volume = "161",
pages = "9--17",
journal = "Comparative Biochemistry and Physiology. Part A: Molecular & Integrative Physiology",
issn = "1095-6433",

}

RIS

TY - JOUR

T1 - Bridging the gap between chemistry, physiology, and evolution: Quantifying the functionality of sperm whale myoglobin mutants

A1 - Dasmeh,Pouria

A1 - Kepp,Kasper Planeta

AU - Dasmeh,Pouria

AU - Kepp,Kasper Planeta

PB - Elsevier Inc.

PY - 2011

Y1 - 2011

N2 - This work merges a large set of previously reported thermochemical data for myoglobin (Mb) mutants with a physiological model of O2-transport and -storage. The model allows a quantification of the functional proficiency of myoglobin (Mb) mutants under various physiological conditions, i.e. O2-consumption rate resembling workload, O2 partial pressure resembling hypoxic stress, muscle cell size, and Mb concentration, resembling different organism-specific and compensatory variables. We find that O2-storage and -transport are distinct functions that rank mutants and wild type differently depending on O2 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 O2-transporters because they still have empty sites for O2, giving rise to a larger [MbO2] 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 O2 pressure. These results together show that conserved residues in wild type (WT) Mb were fixated under a selection pressure of low PO2.

AB - This work merges a large set of previously reported thermochemical data for myoglobin (Mb) mutants with a physiological model of O2-transport and -storage. The model allows a quantification of the functional proficiency of myoglobin (Mb) mutants under various physiological conditions, i.e. O2-consumption rate resembling workload, O2 partial pressure resembling hypoxic stress, muscle cell size, and Mb concentration, resembling different organism-specific and compensatory variables. We find that O2-storage and -transport are distinct functions that rank mutants and wild type differently depending on O2 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 O2-transporters because they still have empty sites for O2, giving rise to a larger [MbO2] 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 O2 pressure. These results together show that conserved residues in wild type (WT) Mb were fixated under a selection pressure of low PO2.

KW - Oxygen transport

KW - Diving

KW - Whale

KW - Physiology

KW - Myoglobin

KW - Muscle cell

KW - Oxygen storage

U2 - 10.1016/j.cbpa.2011.07.027

DO - 10.1016/j.cbpa.2011.07.027

JO - Comparative Biochemistry and Physiology. Part A: Molecular & Integrative Physiology

JF - Comparative Biochemistry and Physiology. Part A: Molecular & Integrative Physiology

SN - 1095-6433

VL - 161

SP - 9

EP - 17

ER -