Disease relevance of asd

• Both pvdH and asd (encoding aspartate beta-semialdehyde dehydrogenase) knockout mutants of Pseudomonas aeruginosa PAO1 were unable to synthesize pyoverdine under iron-limiting conditions in the absence of l-2,4-diaminobutyrate in the culture media [1].
• By subcloning, asd was localized to a 1.24 kb DNA fragment which in an E. coli T7 expression system strongly expressed a 40,000 Da protein [2].
• This was previously exploited to develop vaccine strains of Salmonella typhimurium and cloning vectors containing asd as an in vivo selectable marker [2].
• asd mutants of Gram-negative and some Gram-positive bacteria have an obligate requirement for diaminopimelic acid (DAP), an essential constituent of the cell wall of these organisms [2].

High impact information on asd

• Molecular genetic analysis of the region containing the essential Pseudomonas aeruginosa asd gene encoding aspartate-beta-semialdehyde dehydrogenase [2].
• By PFGE, the asd gene was mapped to between coordinates 1.89 and 2.15 Mbp, or 37-40 min, on the 5.9 Mbp P. aeruginosa chromosome [2].

Analytical, diagnostic and therapeutic context of asd

• As a first step for development of such systems for Pseudomonas aeruginosa, the asd gene from wild-type strain PAO1 was cloned by a combined approach of PCR amplification from chromosomal DNA, construction of mini-libraries and by complementation of an Escherichia coli delta asd mutant [2].

References