Globin X: A highly stable intrinsically hexacoordinate globin.

Autor: Farhana R; Department of Chemistry and Biochemistry, Florida International University, Miami, FL, United States of America., Lei R; Department of Chemistry and Biochemistry, Florida International University, Miami, FL, United States of America., Pham K; Department of Chemistry and Biochemistry, Florida International University, Miami, FL, United States of America., Derrien V; Université Paris-Saclay, CNRS, Institut de Chimie Physique, UMR8000, 91405 Orsay, France., Cedeño J; Department of Chemistry and Biochemistry, Florida International University, Miami, FL, United States of America., Rodriquez V; Department of Chemistry and Biochemistry, Florida International University, Miami, FL, United States of America., Bernad S; Université Paris-Saclay, CNRS, Institut de Chimie Physique, UMR8000, 91405 Orsay, France., Lima FF; Department of Chemistry and Biochemistry, Florida International University, Miami, FL, United States of America; Biomedical Science Institute, Florida International University, Miami, FL, United States of America., Miksovska J; Department of Chemistry and Biochemistry, Florida International University, Miami, FL, United States of America; Biomedical Science Institute, Florida International University, Miami, FL, United States of America. Electronic address: miksovsk@fiu.edu.
Jazyk: angličtina
Zdroj: Journal of inorganic biochemistry [J Inorg Biochem] 2022 Nov; Vol. 236, pp. 111976. Date of Electronic Publication: 2022 Aug 24.
DOI: 10.1016/j.jinorgbio.2022.111976
Abstrakt: Several novel members of the vertebrate globin family were recently discovered with unique structural features that are not found in traditional penta-coordinate globins. Here we combine structural tools to better understand and recognize molecular determinants that contribute to the stability of hexacoordinate globin X (GbX) from Danio rerio (zebrafish). pH-induced unfolding data indicates increased stability of GbX with pH mid of 1.9 ± 0.1 for met GbXWT, 2.4 ± 0.1 for met GbXC65A, and 3.4 ± 0.1 for GbXH90V. These results are in good agreement with GbX unfolding experiments using GuHCl, where a ΔG unf 13.8 ± 2.5 kcal mol -1 and 16.3 ± 2.6 kcal mol -1 are observed for metGbXWT, and metGbXC65A constructs, respectively, and diminished stability is measured for GbXH90V, ΔG unf  = 9.5 ± 3.6 kcal mol -1 . The metGbXWT and metGbXC65A also exhibit high thermal stability (melting points of 118 °C and 107 °C, respectively). Native ion mobility - mass spectrometry (IM-MS) experiments showed a narrow charge state distribution (9-12+) characteristics of a native, structured protein; a single mobility band was observed for the native states. Collision induced unfolding IM-MS experiments showed a two-state transition, in good agreement with the solution studies. GbXWT retains the heme over a wide range of charge states, suggesting strong interactions between the prosthetic group and the apoprotein. The above results indicate that in addition to the disulfide bond and the heme iron hexa-coordination, other structural determinants enhance stability of this protein.
Competing Interests: Declaration of Competing Interest Authors have no conflict of interest.
(Copyright © 2022 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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