Ligand- and proton-linked conformational changes of the ferrous 2/2 hemoglobin of Pseudoalteromonas haloplanktis TAC125.

Abstract

The spectroscopic and ligand-binding properties of a 2/2 globin from the Antarctic bacterium Pseudoalteromonas haloplanktis TAC125 have been studied in the ferrous state. It displays two major conformations characterized by CO-association rates that differ by a factor of 20, with relative fractions that depend on pH. A dynamic equilibrium is found between the two conformations, as indicated by an enhanced slower phase when lower CO levels were used to allow a longer time to facilitate the transition. The deoxy form, in the absence of external ligands, is a mixture of a predominant six-coordinate low spin form and a five-coordinate high-spin state; the proportion of low spin increasing at alkaline pH. In addition, at temperatures above the physiological temperature of 1 °C, an enhanced tendency of the protein to oxidize is observed.

DOI: 10.1002/iub.492

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Cite this paper

@article{Giordano2011LigandAP, title={Ligand- and proton-linked conformational changes of the ferrous 2/2 hemoglobin of Pseudoalteromonas haloplanktis TAC125.}, author={D. Giordano and Roberta Russo and Chiara Ciaccio and Barry D. Howes and Guido di Prisco and M C Michael C Marden and Gaston Hui Bon Hoa and Giulietta Smulevich and Massimo Coletta and Cinzia Verde}, journal={IUBMB life}, year={2011}, volume={63 7}, pages={566-73} }