Methionine-R-sulfoxide reductase B2, mitochondrial (MSRB2)

Methionine-R-sulfoxide reductase B2, mitochondrial (MSRB2), is a zinc-containing oxidoreductase enzyme encoded by the MSRB2 gene in humans and localized to mitochondria[3][5][7][1]. MSRB2 specifically reduces methionine (R)-sulfoxide residues in proteins back to methionine, playing a critical role in the cellular defense against oxidative stress by repairing oxidatively damaged methionine. Structurally, MSRB2 is a globular protein with eight anti-parallel β-strands and three N-terminal α-helices, and a tetrahedral zinc ion stabilizing its top portion[1][2]. Unlike MsrB1, which contains a resolving selenocysteine, MSRB2 uses cysteine as its catalytic residue and does not contain a resolving Cys, leading to different catalytic mechanisms between the two enzymes[1]. MSRB2 contributes to mitochondrial integrity and cell survival by decreasing intracellular reactive oxygen species and maintaining protein function after oxidative insults[3]. It is highly expressed in muscle tissues and less so in the brain[5]. Mutations in MSRB2 are associated with rare congenital disorders and may contribute to broader pathologies via its role in redox homeostasis[3][5].

Other names

Methionine sulfoxide reductase B2MSRB2CBS-1MsrB2PILBCGI-131CBS1

Reduces methionine (R)-sulfoxide back to methionine, thereby repairing oxidative damage to proteins and decreasing ROS build-up