alsS [Fri Nov 13 2015 17:21:21 GMT+0100 (CET)]

acetolactate synthase

locus: BSU36010

pI: 5.00

mw: 61.00 kDa

function: overflow metabolism

product: acetolactate synthase

essential: no

ec: 2.2.1.6

synonyms

Genomic Context

categories

• [category|SW 2|Metabolism] → [category|SW 2.2|Carbon metabolism] → [category|SW 2.2.1|Carbon core metabolism] → [category|SW 2.2.1.5|Overflow metabolism]

[SW|Categories] containing this gene/protein

• [SW|carbon core metabolism]

This gene is a member of the following [SW|regulons]

• [SW|AlsR regulon], [SW|Rex regulon], [SW|stringent response]

Gene

Coordinates on the chromosome (coding sequence): 3,709,628 -> 3,711,340

The protein

Catalyzed reaction/ biological activity

• 2 pyruvate = 2-acetolactate CO₂ (according to Swiss-Prot)

Protein family

• TPP enzyme family (according to Swiss-Prot)

Paralogous protein(s)

• [protein|search|IlvB], [protein|search|YdaP]

[SW|Cofactors]

• Mg² [Pubmed|25393087]
• TPP [Pubmed|25393087]

Structure

• [http://pdb.org/pdb/explore/explore.do?structureId=4rjj [4RJJ]] (complex wit TPP) [Pubmed|25393087]

Expression and Regulation

Operon

• ''[protein|search|alsS]-[protein|search|alsD]'' [Pubmed|7685336]

[SW|Sigma factor]

• [protein|search|SigA] [Pubmed|7685336]

Regulation

• induction by acetate ([protein|search|AlsR]) [Pubmed|7685336]
• repressed as long as terminal electron acceptors are available for respiration ([protein|search|Rex]) [Pubmed|16428414]
• subject to positive stringent control upon lysine starvation [Pubmed|20081037]
• Note: since acetate formation requires ''[protein|search|ackA]'' activation by [protein|search|CcpA] there is an indirect effect of [protein|search|CcpA] on the ''alsSD'' operon: the operon is not expressed in ''[protein|search|ccpA]'' mutants

Regulatory mechanism

• stringent response: due to presence of adenines at 1 and 2 positions of the transcript [Pubmed|20081037]
• [protein|search|AlsR]: transcription activation in the presence of acetate [Pubmed|7685336]
• [protein|search|Rex]: transcription repression if the ratio NADH2/NAD is high [Pubmed|16428414]

Biological materials

Mutant

• 1A979 ( ''alsS''::''cat''), [Pubmed|7685336], available at [http://pasture.asc.ohio-state.edu/BGSC/getdetail.cfm?bgscid=1A979&Search=1A979 BGSC]

References

• 19087206,10986270,20081037,16428414,19383131,7685336,16428414,19684168,24734205,22178965,25393087