Crystal structure of a membrane-bound metalloenzyme that catalyses the biological oxidation of methane

  title={Crystal structure of a membrane-bound metalloenzyme that catalyses the biological oxidation of methane},
  author={Raquel L. Lieberman and Amy C. Rosenzweig},
Particulate methane monooxygenase (pMMO) is an integral membrane metalloenzyme that catalyses the conversion of methane to methanol. Knowledge of how pMMO performs this extremely challenging chemistry may have an impact on the use of methane as an alternative energy source by facilitating the development of new synthetic catalysts. We have determined the structure of pMMO from the methanotroph Methylococcus capsulatus (Bath) to a resolution of 2.8 Å. The enzyme is a trimer with an α3β3γ3… 

The quest for the particulate methane monooxygenase active site.

The state of knowledge before and after the structure determination of pMMO is reviewed, emphasizing elucidation of the pM MO active site.

Structural conservation of the B subunit in the ammonia monooxygenase/particulate methane monooxygenase superfamily

The crystal structure of the corresponding domain of an archaeal amoB subunit from Nitrosocaldus yellowstonii has been determined and reveals a remarkable conservation of overall fold and copper binding site location as well as several notable differences that may have implications for function and stability.

Architecture and active site of particulate methane monooxygenase

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.

Controlled oxidation of hydrocarbons by the membrane-bound methane monooxygenase: the case for a tricopper cluster.

Evidence is described that pMMO is a multicopper protein that mediates dioxygen chemistry and O-atom transfer during alkane hydroxylation and designed and synthesized model tricopper clusters to provide further chemical evidence that a tricoppers cluster mediates the enzyme's oxo-transfer chemistry.

The model structure of the copper-dependent ammonia monooxygenase

A successful attempt to build a structural model of ammonia monooxygenase, and its accessory proteins AmoD and AmoE, from Nitrosomonas europaea, taking advantage of the high sequence similarity with particulate methane mono oxygengenase and the homologous PmoD protein, for which crystal structures are instead available.

Particulate Methane Monooxygenase

Although the identity of the pMMO active site remains unknown, some information regarding the mechanism has been obtained from substrate studies and computational work.

From micelles to bicelles: Effect of the membrane on particulate methane monooxygenase activity

These findings suggest that loss of pMMO activity upon isolation is due to removal from the membranes rather than caused by loss of the catalytic copper ions, and underscore the importance of studying membrane proteins in a membrane-like environment.

A tale of two methane monooxygenases

The current state of knowledge for both enzymes is reviewed, and pMMO O2 activation intermediates suggested by computational and synthetic studies in the context of existing biochemical data are considered.



Crystal structure of a bacterial non-haem iron hydroxylase that catalyses the biological oxidation of methane

The 2.2 & Aring; crystal structure of the 251K α2β2γ2 dimeric hydroxylase protein of methane mono-oxygenase from Methylococcus capsulatus (Bath) reveals the geometry of the catalytic di-iron

Toward delineating the structure and function of the particulate methane monooxygenase from methanotrophic bacteria.

Results are consistent with a concerted mechanism involving direct side-on insertion of an active singlet "oxene" from the activated copper cluster across the "C-H" bond in the active site, and a possible role for the two reductants in the turnover of the enzyme is proposed.

Biological Methane Oxidation: Regulation, Biochemistry, and Active Site Structure of Particulate Methane Monooxygenase

This review summarizes for the first time the often controversial pMMO literature, focusing on recent progress and highlighting unresolved issues.

Methanobactin, a Copper-Acquisition Compound from Methane-Oxidizing Bacteria

Evidence of analogous molecules for copper transport from methane-oxidizing bacteria is presented, represented by a small fluorescent chromopeptide produced by Methylosinus trichosporium OB3b.

Purified particulate methane monooxygenase from Methylococcus capsulatus (Bath) is a dimer with both mononuclear copper and a copper-containing cluster

Extended x-ray absorption fine structure data are best fit with oxygen/nitrogen ligands and a 2.57-Å Cu-Cu interaction, providing direct evidence for a copper-containing cluster in pMMO.

The membrane-associated form of methane mono-oxygenase from Methylococcus capsulatus (Bath) is a copper/iron protein.

The essential role of copper in enzyme catalysis is verified, the implausibility of copper existing as a trinuclear cluster is indicated and the presence of a tightly bound mononuclear Fe(3+) ion in an octahedral environment that may well be exchange-coupled to another paramagnetic species is demonstrated.

Dioxygen Activation and Methane Hydroxylation by Soluble Methane Monooxygenase: A Tale of Two Irons and Three Proteins.

Different aspects of catalysis by the MMO proteins are examined, including the mechanisms of dioxygen activation at the diiron site and substrate hydroxylation by the activated oxygen species.

The Particulate Methane Monooxygenase from Methylococcus capsulatus (Bath) Is a Novel Copper-containing Three-subunit Enzyme

The particulate methane monooxygenase (pMMO) is known to be very difficult to study mainly due to its unusual activity instability in vitro. By cultivatingMethylococcus capsulatus (Bath) under

Structure at 2.8 Å resolution of cytochrome c oxidase from Paracoccus denitrificans

The crystal structure at 2.8 Å resolution of the four protein subunits containing cytochrome c oxidase from the soil bacterium Paracoccus denitrificans, complexed with an antibody Fv fragment, is described and mechanisms for proton pumping are discussed.

Multicopper Oxidases and Oxygenases.

Copper sites have historically been divided into three classes based on their spectroscopic features, which reflect the geometric and electronic structure of the active site: type 1 or blue copper, type 2 (T2) or normal copper, and type 3 (T3) or coupled binuclear copper centers.