Structural characterisation of a MAPR-related archaeal cytochrome b5M protein

Sarah Teakel, Michealla Marama, David Aragão, Sofiya Tsimbalyuk, Emily R.R. Mackie, Tatiana P. Soares da Costa, Jade K. Forwood, Michael A. Cahill

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)
22 Downloads (Pure)


We recently reported that the membrane-associated progesterone receptor (MAPR) protein family (mammalian members: PGRMC1, PGRMC2, NEUFC and NENF) originated from a new class of prokaryotic cytochrome b5 (cytb5) domain proteins, called cytb5M (MAPR-like). Relative to classical cytb5 proteins, MAPR and ctyb5M proteins shared unique sequence elements and a distinct heme-binding orientation at an approximately 90° rotation relative to classical cytb5, as demonstrated in the archetypal crystal structure of a cytb5M protein (PDB accession number 6NZX). Here, we present the crystal structure of an archaeal cytb5M domain (Methanococcoides burtonii WP_011499504.1, PDB:6VZ6). It exhibits similar heme binding to the 6NZX cytb5M, supporting the deduction that MAPR-like heme orientation was inherited from the prokaryotic ancestor of the original eukaryotic MAPR gene.
Original languageEnglish
Pages (from-to)2409-2417
Number of pages9
JournalFEBS Letters
Issue number18
Early online date09 Aug 2022
Publication statusPublished - Sept 2022


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