title: Effects of the loss of the axial tyrosine ligand of the low-spin heme of MauG on its physical properties and reactivity.
abstract: MauG catalyzes posttranslational modifications of methylamine dehydrogenase to complete the biosynthesis of its protein-derived tryptophan tryptophylquinone (TTQ) cofactor. MauG possesses a five-coordinate high-spin and a six-coordinate low-spin ferric heme, the latter with His-Tyr ligation. Replacement of this tyrosine with lysine generates a MauG variant with only high-spin ferric heme and altered spectroscopic and redox properties. Y294K MauG cannot stabilize the bis-Fe(IV) redox state required for TTQ biosynthesis but instead forms a compound I-like species on reaction with peroxide. The results clarify the role of Tyr ligation of the five-coordinate heme in determining the physical and redox properties and reactivity of MauG.
authors.affiliation: Biochemistry and Physiology Department, College of Medicine, The University of Jordan, Amman 11942, Jordan.
authors.forename: Nafez
authors.initials: N
authors.lastname: Abu Tarboush
authors.forename: Sooim
authors.initials: S
authors.lastname: Shin
authors.forename: Jiafeng
authors.initials: J
authors.lastname: Geng
authors.forename: Aimin
authors.initials: A
authors.lastname: Liu
authors.forename: Victor L
authors.initials: VL
authors.lastname: Davidson
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D006418:Heme / Q000737:chemistry*; D000081062:Heme-Binding Proteins; D006420:Hemeproteins / Q000378:metabolism*; D006639:Histidine / Q000737:chemistry; D045563:Indolequinones / Q000096:biosynthesis; D008024:Ligands; D008239:Lysine / Q000737:chemistry; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000378:metabolism; D010231:Paracoccus denitrificans / Q000201:enzymology*; D010545:Peroxides / Q000737:chemistry; D011499:Protein Processing, Post-Translational; D013053:Spectrophotometry; D014364:Tryptophan / Q000031:analogs & derivatives / Q000096:biosynthesis; D014443:Tyrosine / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D000081062:Heme-Binding Proteins; D006420:Hemeproteins; D045563:Indolequinones; D008024:Ligands; D010545:Peroxides; C404449:heme protein, bacteria; C070569:tryptophan tryptophylquinone; D014443:Tyrosine; D006418:Heme; D006639:Histidine; D014364:Tryptophan; C021567:methylamine dehydrogenase; D000587:Oxidoreductases Acting on CH-NH Group Donors; D008239:Lysine