Physiological Studies of Methane- and Methanol-Oxidizing Bacteria: Immunological Comparison of a Primary Alcohol Dehydrogenase from Methylococcus capsulatus and Pseudomonas sp. M27

Abstract

A primary alcohol dehydrogenase was purified from cell extracts of two apparently unrelated microorganisms, namely, Pseudomonas sp. M27 and Methylococcus capsulatus. Rabbit antiserum prepared against the purified enzyme from M. capsulatus revealed distinctive antigenic determinants by quantitative and gel precipitin reactions. Rabbit antiserum to M27 enzyme detected both distinctive and shared antigenic determinants. Certain methaneand methanol-oxidizing bacteria were grouped on the basis of serological cross-reacting enzyme specificities. Pseudomonas sp. M27 and Methylococcus capsulatus are representative of two apparently unrelated groups of microorganisms (1, 18). Nevertheless, the two organisms are similar in certain physiological properties, particularly with reference to the oxidation of C-1 compounds. For example, cell suspensions of both organisms oxidize methane, methanol, formaldehyde, and formate to carbon dioxide (18). Recently, a nonspecific primary alcohol dehydrogenase (PAD) was purified from cell extracts of methanol-grown M. capsulatus and Pseudomonas M27 (2, 17). A comparison of the biochemical and physical properties of the PAD from the two organisms showed similarities in substrate specificity, requirement for ammonium ions, molecular weight, and subunit composition. Also, the purified enzymes had identical absorption properties, with optima occurring at 260 and 350 nm. It was suggested, therefore, that the enzymes operate by identical oxidative mechanisms, perhaps involving a heretofore unknown pteridine derivative (17). The purified enzymes, however, differ in their electrophoretic mobilities (17). Disc gel

Alcohol Dehydrogenase from Methylobacterium organophilum

“…Wadzinski and Rib-bons reported that the methanol-oxidizing enzyme in M. capsulatus was membrane bound (26). Antiserum prepared against the purified enzyme from M. capsulatus was very specific and did not cross-react with the enzymes from facultative methylotrophs (15). The current study also suggests that serologically different alcohol dehydrogenases exist in the Methylococ-cus organisms and the facultative methylotrophs.…”

“…The enzymes exhibited broad substrate specificity for primary aliphatic alcohols and were also capable of oxidizing fornaldehyde to formate. Immunological and biochemical studies comparing the enzymes of an obligate methylotroph and a facultative organism have suggested a close relationship between these organisms in spite of differences in their carbon assimilation pathways (14,15).…”

Microbial Oxidation of Methane and Methanol: Crystallization of Methanol Dehydrogenase and Properties of Holo- and Apo-Methanol Dehydrogenase from Methylomonas methanica

“…Subsequently, a similar soluble methanol dehydrogenase was isolated from a type I obligate methylotroph, Methylococcus capsulatus (15), and from various methanol-utliing bacteria (24). Recently, we crystallized methanol dehydrogenase from the type II obligate methylotroph Methylosinus sporium (18). (27) reported that M. capsulatus contained particulate PMS-independent methanol oxidase, particulate PMS-dependent methanol dehydrogenase, and soluble PMS-dependent methanol dehydrogenase activities.…”

Oxidation of C1 compounds by particulate fractions from Methylococcus capsulatus: properties of methanol oxidase and methanol dehydrogenase

“…A variety of soluble methanol oxidizing enzymes have been isolated from both obligate and nonobligate methyltrophs (1-6, 13, 14, 16, 19-21, 25). The two systems, which have been well characterized, are: (i) the pteridin methanol dehydrogenases first obtained from Pseudomonas M27 by Anthony and Zatman (1-5) and later from the obligate methylotroph Methylococcus capsulatus (19)(20)(21) in pure form; and (ii) the flavoprotein methanol oxidases from yeasts (13,25). The quantitative importance of these activities has not always been clear except in the case of mutants of Pseudomonas AM1 which lack methanol dehydrogenase activity and are unable to grow on methanol (15).…”