Investigation of the prevalence and catalytic activity of rubredoxin-fused alkane monooxygenases (AlkBs)

J Inorg Biochem. 2021 Jun:219:111409. doi: 10.1016/j.jinorgbio.2021.111409. Epub 2021 Mar 16.


Interest in understanding the environmental distribution of the alkane monooxygenase (AlkB) enzyme led to the identification of over 100 distinct alkane monooxygenase (AlkB) enzymes containing a covalently bound, or fused, rubredoxin. The rubredoxin-fused AlkB from Dietzia cinnamea was cloned as a full-length protein and as a truncated protein with the rubredoxin domain deleted. A point mutation (V91W) was introduced into the full-length protein, with the goal of assessing how steric bulk in the putative substrate channel might affect selectivity. Based on activity studies with alkane and alkene substrates, the rubredoxin-fused AlkB oxidizes a similar range of alkane substrates relative to its rubredoxin domain-deletion counterpart. Oxidation of terminal alkenes generated both an epoxide and a terminal aldehyde. The products of V91W-mutant-catalyzed oxidation of alkenes had a higher aldehyde-to-epoxide ratio than the products formed in the presence of the wild type protein. These results are consistent with this mutation causing a structural change impacting substrate positioning.

Keywords: AlkB; Alkane oxidation; Biocatalysis; Diiron enzymes; Monooxygenase; Rubredoxin.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actinobacteria / genetics
  • Actinobacteria / metabolism
  • Alkanes / chemistry
  • Alkanes / metabolism*
  • Alkenes / metabolism
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Catalysis
  • Computational Biology / methods
  • Humans
  • Mixed Function Oxygenases / chemistry
  • Mixed Function Oxygenases / genetics
  • Mixed Function Oxygenases / metabolism*
  • Oxidation-Reduction
  • Point Mutation
  • Prevalence
  • Rubredoxins / chemistry
  • Rubredoxins / metabolism*


  • Alkanes
  • Alkenes
  • Bacterial Proteins
  • Rubredoxins
  • Mixed Function Oxygenases

Supplementary concepts

  • Dietzia cinnamea