Truncated (2/2) hemoglobin: Unconventional structures and functional roles in vivo and in human pathogenesis.

Autor: Nardini M; Department of Biosciences, University of Milano, Milano, Italy., Pesce A; Department of Physics, University of Genova, Genova, Italy., Bolognesi M; Department of Biosciences, University of Milano, Milano, Italy. Electronic address: martino.bolognesi@unimi.it.
Jazyk: angličtina
Zdroj: Molecular aspects of medicine [Mol Aspects Med] 2022 Apr; Vol. 84, pp. 101049. Date of Electronic Publication: 2021 Nov 12.
DOI: 10.1016/j.mam.2021.101049
Abstrakt: Truncated hemoglobins (trHbs) build a sub-class of the globin family, found in eubacteria, cyanobacteria, unicellular eukaryotes, and in higher plants; among these, selected human pathogens are found. The trHb fold is based on a 2/2 α-helical sandwich, consisting of a simplified and reduced-size version of the classical 3/3 α-helical sandwich of vertebrate and invertebrate globins. Phylogenetic analysis indicates that trHbs further branch into three groups: group I (or trHbN), group II (or trHbO), and group III (or trHbP), each group being characterized by specific structural features. Among these, a protein matrix tunnel, or a cavity system implicated in diatomic ligand diffusion through the protein matrix, is typical of group I and group II, respectively. In general, a highly intertwined network of hydrogen bonds stabilizes the heme bound ligand, despite variability of the heme distal residues in the different trHb groups. Notably, some organisms display genes from more than one trHb group, suggesting that trHbN, trHbO, and trHbP may support different functions in vivo, such as detoxification of reactive nitrogen and oxygen species, respiration, oxygen storage/sensoring, thus aiding survival of an invading microorganism. Here, structural features and proposed functions of trHbs from human pathogens are reviewed.
(Copyright © 2021 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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