ISSN:
1432-072X
Keywords:
Key words Archaea
;
Methanococcus
;
Methane
;
formation
;
Hydrogenases
;
H2-Forming dehydrogenase
;
N5
;
N10-Methylenetetrahydromethanopterin
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract H2-Forming N 5 ,N 10 -methylenetetrahydromethanopterin dehydrogenase (Hmd) is a novel type of hydrogenase found in methanogenic Achaea that contains neither nickel nor iron-sulfur clusters. The enzyme has previously been characterized from Methanobacterium thermoautotrophicum and from Methanopyrus kandleri. We report here on the purification and properties of the enzyme from Methanococcus thermolithotrophicus. The hmd gene was cloned and sequenced. The results indicate that the enzyme from Mc. thermolithotrophicus is functionally and structurally closely related to the H2-forming methylene tetrahydromethanopterin dehydrogenase from Mb. thermoautotrophicum and Mp. kandleri. From amino acid sequence comparisons of the three enzymes, a phylogenetic tree was deduced that shows branching orders similar to those derived from sequence comparisons of the 16S rRNA of the orders Methanococcales, Methanobacteriales, and Methanopyrales.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01692860
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