Abstract
The iron-sulfur-cluster-free hydrogenase Hmd (H(2)-forming methylenetetrahydromethanopterin dehydrogenase) from methanogenic archaea has recently been found to contain one iron associated tightly with an extractable cofactor of yet unknown structure. We report here that Hmd contains intrinsic CO bound to the Fe. Chemical analysis of Hmd revealed the presence of 2.4 +/- 0.2 mol of CO/mol of iron. Fourier transform infrared spectra of the native enzyme showed two bands of almost equal intensity at 2011 and 1944 cm(-)(1), interpreted as the stretching frequencies of two CO molecules bound to the same iron in an angle of 90 degrees . We also report on the effect of extrinsic (12)CO, (13)CO, (12)CN(-), and (13)CN(-) on the IR spectrum of Hmd.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Archaeal Proteins / chemistry
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Archaeal Proteins / metabolism
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Binding Sites
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Binding, Competitive
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Carbon Isotopes
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Carbon Monoxide / chemistry*
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Carbon Monoxide / metabolism
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Cyanides / chemistry
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Cyanides / metabolism
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Hydrogen / chemistry
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Hydrogen-Ion Concentration
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Iron Compounds / chemistry*
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Iron Compounds / metabolism
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Light
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Methanobacteriaceae / enzymology
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Oxidoreductases Acting on CH-NH Group Donors / chemistry*
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Oxidoreductases Acting on CH-NH Group Donors / metabolism
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Oxygen / chemistry
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Pterins / chemistry
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Pterins / metabolism
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Spectrophotometry, Infrared
Substances
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Archaeal Proteins
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Carbon Isotopes
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Cyanides
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Iron Compounds
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N(5),N(10)-methylene-tetrahydromethanopterin
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Pterins
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Carbon Monoxide
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Hydrogen
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Oxidoreductases Acting on CH-NH Group Donors
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methylenetetrahydromethanopterin dehydrogenase
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Oxygen