Maturation of [NiFe]-hydrogenases often involves specific proteases responsible for cleavage of the catalytic subunits.
Escherichia coli
HycI is the protease dedicated to maturation of the Hydrogenase-3 isoenzyme, a component of formate hydrogenlyase-1. In this work, it is demonstrated that a
Pectobacterium atrosepticum
HycI homologue, HyfK, is required for hydrogenase-4 activity, a component of formate hydrogenlyase-2, in that bacterium. The
P. atrosepticum
ΔhyfK mutant phenotype could be rescued by either P. atrosepticum hyfK or E. coli hycI on a plasmid. Conversely, an
E. coli
ΔhycI mutant was complemented by either E. coli hycI or P. atrosepticum hyfK in trans. E. coli is a rare example of a bacterium containing both hydrogenase-3 and hydrogenase-4, however the operon encoding hydrogenase-4 has no maturation protease gene. This work suggests HycI should be sufficient for maturation of both
E. coli
formate hydrogenlyases, however no formate hydrogenlyase-2 activity was detected in any
E. coli
strains tested here.
The plant pathogen
Pectobacterium atrosepticum
contains a functional formate hydrogenlyase‐2 complex