[39] Methylamine dehydrogenase from methylobacillus flagellatum

Kiriukhin, Michael Y.; Chistoserdov, A. Y.; Tsygankov, Y. D.

doi:10.1016/0076-6879(90)88041-8

Cited by 13 publications

(11 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…MADHs from M. extorquens AMI and M. flagellatum KT were purified as described previously (30). Rabbit antibodies against MADH from M. flagellatum 5902 CHISTOSERDOV ET AL.…”

Section: Methodsmentioning

confidence: 99%

“…The enzyme consists of two large and two small (14-kDa) subunits (51), with a cofactor covalently bound to the small subunit. MADHs from other methylotrophic bacteria have a similar structure (23, 27, 42, 51), except the MADH from Methylobacillus flagellatum KT, which is a heterodimer (30). Amino acid (28) and nucleotide (14) sequences of the small subunit of MADH from M. extorquens AM1 have been published.…”

mentioning

confidence: 99%

“…(11,12,15,29); and obligate methylotrophs such as Methylobacillus spp. (22,30,41) and "Methylomonas" spp. (42,44).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Genetic organization of methylamine utilization genes from Methylobacterium extorquens AM1

1991

View full text Add to dashboard Cite

An isolated 5.2-kb fragment of Methylobacterium extorquens AM1 DNA was found to contain a gene cluster involved in methylamine utilization. Analysis of polypeptides synthesized in an Escherichia coli T7 expression system showed that five genes were present. Two of the genes encoded the large and small subunits of methylamine dehydrogenase, and a third encoded amicyanin, the presumed electron acceptor for methylamine dehydrogenase, but the function of the other two genes is not known. The order on the 5.2-kb fragment was found to be large-subunit gene, the two genes of unknown function, small-subunit gene, amicyanin gene. The gene for azurin, another possible electron acceptor in methylamine oxidation, does not appear to be present within this cluster of methylamine utilization genes.Gram-negative bacteria of diverse systematic groups are able to utilize methylamine as a carbon, energy, and nitrogen source. These groups include facultative autotrophs such as Paracoccus denitrificans (25) (45,56), and all nonpigmented "Pseudomonas" strains (5,7,24,32).Methylobacterium extorquens AM1 utilizes methylamine via MADH (18). The enzyme consists of two large and two small (14-kDa) subunits (51), with a cofactor covalently bound to the small subunit. MADHs from other methylotrophic bacteria have a similar structure (23, 27, 42, 51), except the MADH from Methylobacillus flagellatum KT, which is a heterodimer (30). Amino acid (28) and nucleotide (14) sequences of the small subunit of MADH from M. extorquens AM1 have been published. Recent evidence has shown that the MADH cofactor has a unique structure, having two tryptophans within the polypeptide chain that are modified and covalently linked (14). A novel structure has been proposed for this cofactor (43).The copper-containing protein amicyanin is proposed to be the natural electron acceptor for MADH (17,25,34,35,54,55,57,58 Another copper-containing protein, azurin, has been found in M. extorquens AML. It accepts electrons in vitro from amicyanin, cytochrome CL, or cytochrome CH and transfers them to a terminal oxidase (54). However, it is induced only in the presence of high concentrations of copper in the growth medium. Azurin is also induced by high copper concentrations in M. flagellatum KT (17), "Methylomonas" strain J (54), and P. denitrificans (40).Although the first step of methylamine oxidation has been well studied biochemically, little is known about the organization of genes involved in methylamine metabolism. Recently, we reported the cloning and sequencing of the genes for the small subunit of MADH (14)

show abstract

“…MADHs from M. extorquens AMI and M. flagellatum KT were purified as described previously (30). Rabbit antibodies against MADH from M. flagellatum 5902 CHISTOSERDOV ET AL.…”

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Genetic organization of methylamine utilization genes from Methylobacterium extorquens AM1

1991

View full text Add to dashboard Cite

show abstract

“…In all cases that have been studied, MADH has been a periplasmic protein consisting of two large subunits and two small subunits (17,20,(22)(23)(24)27). Each small subunit has a covalently bound prosthetic group called tryptophan tryptophylquinone synthesized from two tryptophans belonging to the small-subunit polypeptide chain (28).…”

mentioning

confidence: 99%

“…Methylamine dehydrogenase (MADH) is the enzyme that oxidizes methylamine to formaldehyde in many gram-negative bacteria that grow on methylamine (13,17,20,(21)(22)(23)(24)27). In all cases that have been studied, MADH has been a periplasmic protein consisting of two large subunits and two small subunits (17,20,(22)(23)(24)27).…”

mentioning

confidence: 99%

Cloning, sequencing, and mutation of a gene for azurin in Methylobacillus flagellatum KT

1995

View full text Add to dashboard Cite

The gene cluster for methylamine utilization (mau genes) has been cloned from the obligate methylotrophic bacterium Methylobacillus flagellatum KT. Partial sequence data showed that the organization of these genes was similar to that found in Methylophilus methylotrophus W3A1-NS, including the lack of a gene for amicyanin, which had been thought to be the electron acceptor for methylamine dehydrogenase in M. flagellatum KT. However, a gene encoding azurin was discovered at the 3 end of the mau gene cluster, transcribed in the opposite orientation. A mutant with a defect in this gene showed impaired growth on methylamine, suggesting that azurin is involved in methylamine oxidation in M. flagellatum KT.Methylamine dehydrogenase (MADH) is the enzyme that oxidizes methylamine to formaldehyde in many gram-negative bacteria that grow on methylamine (13,17,20,(21)(22)(23)(24)27). In all cases that have been studied, MADH has been a periplasmic protein consisting of two large subunits and two small subunits (17,20,(22)(23)(24)27). Each small subunit has a covalently bound prosthetic group called tryptophan tryptophylquinone synthesized from two tryptophans belonging to the small-subunit polypeptide chain (28). Two types of electron acceptors for MADH are known. MADH is thought to use a c-type cytochrome in Methylophilus strains (4, 6), whereas MADHs from the other methylotrophs are thought to use blue copper proteins, or cupredoxins, as electron acceptors (2,11,19,24,31,32,34). Three classes of cupredoxins are found in methylotrophs, amicyanins, azurins, and pseudoazurins. By definition, the cupredoxin that accepts electrons from MADH is usually termed amicyanin (2). However, for at least one methylotroph, Methylomonas sp. strain J, the amino acid composition shows this cupredoxin to be an azurin. Several methylotrophs, including Methylobacillus flagellatum KT, are known to have two cupredoxins (1,2,11,24). For M. flagellatum KT, one was methylamine inducible and was assumed to be amicyanin (11). In two strains, organism 4025 and M. flagellatum KT, cells can grow slowly on methylamine in a medium depleted of copper, conditions under which cupredoxins are absent (11,24). An unknown cytochrome was suspected to function under such growth conditions, since the known cytochrome c's in these bacteria do not accept electrons from MADH in vitro.Genetic analysis has shown that in the ␣-proteobacteria containing MADH, the genes required for synthesis of active MADH (mau genes) are clustered and include a gene encoding amicyanin (7,8,33,35). The mau gene cluster of Methylophilus methylotrophus W3A1-NS is similar except that it does not include the amicyanin gene, as expected, since this strain does not contain amicyanin (9). Since the electron acceptor for MADH in M. flagellatum KT is uncertain, we have analyzed the mau gene cluster of this bacterium to determine whether the amicyanin gene was present.Escherichia coli DH5␣ (New England Biolabs) was grown in Luria-Bertani medium in the presence of appropriate antibiotics as describ...

show abstract

Quantum study of the structure of the active site of methylamine dehydrogenase

Pierdominici‐Sottile

Echave

Palma

2005

Int J of Quantum Chemistry

View full text Add to dashboard Cite

ABSTRACT:In this article we present the results of a quantum study performed on different models of the active site of methylamine dehydrogenase (MADH). This enzyme catalyzes the oxidation of methylamine to produce formaldehyde and ammonia. During the rate-determinant step of the reaction, a proton is transferred from the methyl group of the substrate to one of the bases of the active site. We performed calculations on three different models of the active site. The number of atoms of the models ranges from 68 to 95. Minimizations and optimizations were performed at the PM3 level of theory. The energies of the optimized structures were then recalculated at the B3LYP 6-31G(d) level. From these energies, we calculated the barriers for H ϩ transfer toward the putative acceptors of the proton Asp76 and Thr122. By comparing the results of different models against each other, we drew some conclusions about the role of different residues. We found that the H ϩ transfer from the substrate toward Thr122 requires that this residue be ionized. The estimated barrier for this ionization was found to be Ͼ19 kcal/mol. The barrier for H ϩ transfer from the substrate toward Asp76 is significantly smaller. Our best estimates indicate that this barrier is 9.7 kcal/ mol, when the imino group of the substrate is unprotonated and 7.7 kcal/mol when it is protonated. We thoroughly discussed the agreement and disagreement of these values with the results reported in previous theoretical and experimental studies.

show abstract

[39] Methylamine dehydrogenase from methylobacillus flagellatum

Cited by 13 publications

References 7 publications

Genetic organization of methylamine utilization genes from Methylobacterium extorquens AM1

Genetic organization of methylamine utilization genes from Methylobacterium extorquens AM1

Cloning, sequencing, and mutation of a gene for azurin in Methylobacillus flagellatum KT

Quantum study of the structure of the active site of methylamine dehydrogenase

Contact Info

Product

Resources

About