Architecture and active site of particulate methane monooxygenase

Megen A. Culpepper, Amy C. Rosenzweig*

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

117 Scopus citations


Particulate methane monooxygenase (pMMO) is an integral membrane metalloenzyme that oxidizes methane to methanol in methanotrophic bacteria, organisms that live on methane gas as their sole carbon source. Understanding pMMO function has important implications for bioremediation applications and for the development of new, environmentally friendly catalysts for the direct conversion of methane to methanol. Crystal structures of pMMOs from three different methanotrophs reveal a trimeric architecture, consisting of three copies each of the pmoB, pmoA, and pmoC subunits. There are three distinct metal centers in each protomer of the trimer, mononuclear and dinuclear copper sites in the periplasmic regions of pmoB and a mononuclear site within the membrane that can be occupied by copper or zinc. Various models for the pMMO active site have been proposed within these structural constraints, including dicopper, tricopper, and diiron centers. Biochemical and spectroscopic data on pMMO and recombinant soluble fragments, denoted spmoB proteins, indicate that the active site involves copper and is located at the site of the dicopper center in the pmoB subunit. Initial spectroscopic evidence for O2 binding at this site has been obtained. Despite these findings, questions remain about the active site identity and nuclearity and will be the focus of future studies.

Original languageEnglish (US)
Pages (from-to)483-492
Number of pages10
JournalCritical Reviews in Biochemistry and Molecular Biology
Issue number6
StatePublished - Dec 2012


  • Ammonia monooxygenase
  • Copper
  • Cu-ZSM-5 zeolite
  • Dioxygen activation
  • Hemocyanin
  • Membrane protein
  • Methanotroph
  • Tyrosinase

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology


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