Biosynthesis of Proline.

Proline was among the last biosynthetic precursors to have its biosynthetic pathway unraveled. This review recapitulates the findings on the biosynthesis and transport of proline. Glutamyl kinase (GK) catalyzes the ATP-dependent phosphorylation of L-glutamic acid.

Crystal structure of Escherichia coli alkanesulfonate monooxygenase SsuD.

The FMNH(2)-dependent alkanesulfonate monooxygenase SsuD catalyzes the conversion of alkanesulfonates to the corresponding aldehyde and sulfite. The enzyme allows Escherichia coli to use a wide range of alkanesulfonates as sulfur sources for growth when sulfate or cysteine are not available. The structure of SsuD was solved using the multiwavelength anomalous dispersion method from only four ordered selenium sites per asymmetric unit (one site per 20,800 Da).

Chloromethane-induced genes define a third C1 utilization pathway in Methylobacterium chloromethanicum CM4.

Methylobacterium chloromethanicum CM4 is an aerobic alpha-proteobacterium capable of growth with chloromethane as the sole carbon and energy source. Two proteins, CmuA and CmuB, were previously purified and shown to catalyze the dehalogenation of chloromethane and the vitamin B12-mediated transfer of the methyl group of chloromethane to tetrahydrofolate. Three genes located near cmuA and cmuB, designated metF, folD and purU and encoding homologs of methylene tetrahydrofolate (methylene-H4folate) reductase, methylene-H4folate dehydrogenase-methenyl-H4folate cyclohydrolase and formyl-H4folate hydrolase, respectively, suggested the existence of a chloromethane-specific oxidation pathway from methyl-tetrahydrofolate to formate in strain CM4.

Transformation of isopropylamine to L-alaninol by Pseudomonas sp. strain KIE171 involves N-glutamylated intermediates.

Pseudomonas sp. strain KIE171 was able to grow with isopropylamine or L-alaninol [S-(+)-2-amino-1-propanol] as the sole carbon source, but not with D-alaninol. To investigate the hypothesis that L-alaninol is an intermediate in the degradation of isopropylamine, two mini-Tn5 mutants unable to utilize both isopropylamine and L-alaninol were isolated.

Pseudomurein endoisopeptidases PeiW and PeiP, two moderately related members of a novel family of proteases produced in Methanothermobacter strains.

Sequence comparison of pseudomurein endoisopeptidases PeiW encoded by the defective prophage PsiM100 of Methanothermobacter wolfeii, and PeiP encoded by phage PsiM2 of Methanothermobacter marburgensis, revealed that the two enzymes share only limited similarity. Their amino acid sequences comprise an N-terminal domain characterized by the presence of direct repeats and a C-terminal domain with a catalytic triad C-H-D as in thiol proteases and animal transglutaminases. Both PeiW and PeiP catalyze the in vitro lysis of M.

Sequence variation in dichloromethane dehalogenases/glutathione S-transferases.

Dichloromethane dehalogenase/glutathione S-transferase allows methylotrophic bacteria to grow with dichloromethane (DCM), a predominantly man-made compound. Bacteria growing with DCM by virtue of this enzyme have been readily isolated in the past. So far, the sequence of the dcmA gene encoding DCM dehalogenase has been determined for Methylobacterium dichloromethanicum DM4 and Methylophilus sp.

Bacillus subtilis genes for the utilization of sulfur from aliphatic sulfonates.

A 5 kb region upstream of katA at 82 degrees on the Bacillus subtilis chromosome contains five ORFs organized in an operon-like structure. Based on sequence similarity, three of the ORFs are likely to encode an ABC transport system (ssuBAC) and another to encode a monooxygenase (ssuD). The deduced amino acid sequence of the last ORF (ygaN) shows no similarity to any known protein.

Regulation of the sulfate starvation response in Pseudomonas aeruginosa: role of cysteine biosynthetic intermediates.

Pseudomonas aeruginosa PAO1 grew in defined synthetic medium with any of a broad variety of single sulfur sources, including sulfate, cysteine, thiocyanate, alkanesulfonates, organosulfate esters and methionine, but not with aromatic sulfonates, thiophenols or organothiocyanates or isothiocyanates. During growth with any of these compounds except sulfate, cysteine or thiocyanate, a set of 10 sulfate starvation-induced (SSI) proteins was strongly up-regulated, as observed by two-dimensional protein electrophoresis of total cell extracts. A comparable level of up-regulation was found for the hydrolytic enzyme arylsulfatase, which has previously been used as a marker enzyme for the sulfate starvation response.

Regulation of the degradative pathways from 4-toluenesulphonate and 4-toluenecarboxylate to protocatechuate in T-2.

T-2 was grown in salts medium containing intermediates of the established, inducible degradative pathway(s) for 4-toluenesulphonate/4-toluenecarboxylate. The specific activity or, if appropriate, the specific expression of pathway enzymes or their components was constant throughout growth and decreased only slowly in the stationary phase. It was found that the 4-toluenesulphonate methyl-monooxygenase system and 4-sulphobenzyl alcohol dehydrogenase (with 4-sulphobenzaldehyde dehydrogenase) were always co-induced, with similar ratios of their activities during growth with 4-toluenesulphonate, 4-toluenecarboxylate and 4-sulphobenzoate.