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Structure of cytochrome b5 unique to tardigrades.

ABSTRACT: Cytochrome b5 is an essential electron transfer protein, which is ubiquitously found in living systems and involved in wide variety of biological processes. Tardigrades (also known as water bears), some of which are famous for desiccation resistance, have many proteins unique to them. Here, we report spectroscopic and structural characterization of a cytochrome b5 like protein from one of the desiccation-tolerant tardigrades, Ramazzottius varieornatus strain YOKOZUNA-1 (RvCytb5 ). A 1.4 Å resolution crystal structure revealed that RvCytb5 is a new cytochrome b5 protein specific to tardigrades.

SUBMITTER: Fukuda Y

PROVIDER: S-EPMC7380671 | biostudies-literature | 2020 Aug

REPOSITORIES: biostudies-literature

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Structure of cytochrome b5 unique to tardigrades.

Fukuda Yohta Y Kim JeeEun J Inoue Tsuyoshi T

Protein science : a publication of the Protein Society 20200801 8

Cytochrome b5 is an essential electron transfer protein, which is ubiquitously found in living systems and involved in wide variety of biological processes. Tardigrades (also known as water bears), some of which are famous for desiccation resistance, have many proteins unique to them. Here, we report spectroscopic and structural characterization of a cytochrome b5 like protein from one of the desiccation-tolerant tardigrades, Ramazzottius varieornatus strain YOKOZUNA-1 (RvC ...[more]

PMID: 32483879

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Project description:Membrane cytochrome b5 reductase is a pleiotropic oxidoreductase that uses primarily soluble reduced nicotinamide adenine dinucleotide (NADH) as an electron donor to reduce multiple biological acceptors localized in cellular membranes. Some of the biological acceptors of the reductase and coupled redox proteins might eventually transfer electrons to oxygen to form reactive oxygen species. Additionally, an inefficient electron transfer to redox acceptors can lead to electron uncoupling and superoxide anion formation by the reductase. Many efforts have been made to characterize the involved catalytic domains in the electron transfer from the reduced flavoprotein to its electron acceptors, such as cytochrome b5, through a detailed description of the flavin and NADH-binding sites. This information might help to understand better the processes and modifications involved in reactive oxygen formation by the cytochrome b5 reductase. Nevertheless, more than half a century since this enzyme was first purified, the one-electron transfer process toward potential electron acceptors of the reductase is still only partially understood. New advances in computational analysis of protein structures allow predicting the intramolecular protein dynamics, identifying potential functional sites, or evaluating the effects of microenvironment changes in protein structure and dynamics. We applied this approach to characterize further the roles of amino acid domains within cytochrome b5 reductase structure, part of the catalytic domain, and several sensors and structural domains involved in the interactions with cytochrome b5 and other electron acceptors. The computational analysis results allowed us to rationalize some of the available spectroscopic data regarding ligand-induced conformational changes leading to an increase in the flavin adenine dinucleotide (FAD) solvent-exposed surface, which has been previously correlated with the formation of complexes with electron acceptors.

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Structure of cytochrome b5 unique to tardigrades.

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Structure of cytochrome b<sub>5</sub> unique to tardigrades.

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