ZABOROSCH, Christiane;
SCHNEIDER, Klaus;
SCHLEGEL, Hans G.;
KRATZIN, Hartmut
Comparison of the NH2‐terminal amino acid sequences of the four non‐identical subunits of the NAD‐linked hydrogenases from Nocardia opaca 1b and Alcaligenes eutrophus H16
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Medientyp:
E-Artikel
Titel:
Comparison of the NH2‐terminal amino acid sequences of the four non‐identical subunits of the NAD‐linked hydrogenases from Nocardia opaca 1b and Alcaligenes eutrophus H16
Beteiligte:
ZABOROSCH, Christiane;
SCHNEIDER, Klaus;
SCHLEGEL, Hans G.;
KRATZIN, Hartmut
Beschreibung:
<jats:p>The cytoplasmic, NAD‐linked hydrogenase of the Gram‐positive hydrogen‐oxidizing bacterium <jats:italic>Nocardia opaca</jats:italic> 1b was compared with the analogous enzyme isolated from the Gram‐negative bacterium <jats:italic>Alcaligenes eutrophus</jats:italic> H16. The hydrogenase of <jats:italic>N. opaca</jats:italic> 1b was purified by a new procedure applying chromatography on phenyl‐Sepharose and DEAE‐Sephacel with two columns in series. A homogeneous enzyme preparation with a specific activity of 74 μmol H<jats:sub>2</jats:sub> oxidized · min<jats:sup>−1</jats:sup>· mg protein<jats:sup>−1</jats:sup> and a yield of 32% was isolated. The <jats:italic>A. eutrophus</jats:italic> enzyme was purified as previously published. Both enzymes are tetrameric proteins composed of four non‐identical subunits (α, β, γ, δ). The four subunits of both of these enzymes were separated and isolated as single polypeptides by preparative polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate.</jats:p><jats:p>Immunological comparison of the four subunits of the <jats:italic>Nocardia</jats:italic> hydrogenase with those of the <jats:italic>Alcaligenes</jats:italic> enzyme showed that the α, β, γ, and δ subunits of one organism were serologically related to the analogous subunits of the other organism. Among themselves, the four subunits do not have any serological relationship.</jats:p><jats:p>The eight individual polypeptides were also compared with respect to the NH<jats:sub>2</jats:sub>‐terminal amino acid sequences determined by automated Edman degradation and to the amino acid compositions. Strong sequence similarities exist between the analogous subunits isolated from the two bacteria. Within the established N‐terminal sequences the similarities between both (α, β, γ, and δ) subunits amount to 63%, 79%, 80% and 65%, respectively. No similarities exist between the different, non‐analogous subunits α, β, γ, and δ.</jats:p>