sasA [Tue Dec 13 2016 11:16:37 GMT+0100 (CET)]

(p)ppGpp synthetase, small alarmone synthetase

locus: BSU38480

pI: 6.00

mw: 24.00 kDa

function: ppGpp synthesis independent from stringent response

product: (p)ppGpp synthetase

essential: no

synonyms: ywaC, relP, ipa-7d

Genomic Context

categories

• [category|SW 2|Metabolism] → [category|SW 2.5|Nucleotide metabolism] → [category|SW 2.5.3|Metabolism of signalling nucleotides]
• [category|SW 4|Lifestyles] → [category|SW 4.3|Coping with stress] → [category|SW 4.3.2|Cell envelope stress proteins (controlled by SigM, V, W, X, Y)]

[SW|Categories] containing this gene/protein

• [SW|metabolism of signalling nucleotides], [SW|cell envelope stress proteins (controlled by SigM, V, W, X, Y)]

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

• [SW|SigM regulon], [SW|SigW regulon]

Gene

Coordinates on the chromosome (coding sequence): 3,949,952 -> 3,950,584

Phenotypes of a mutant

• a ''[protein|search|relA] [protein|search|sasA] [protein|search|sasB]'' triple mutant requires branched chain amino acids, methionine and threonine for growth, the requirement can be suppressed by reduced expression of ''[protein|search|guaB]'' or inactivation of ''[protein|search|codY]'' [Pubmed|24163341]
• a ''[protein|search|relA] [protein|search|sasA] [protein|search|sasB]'' triple mutant acquires suppressor mutations in ''[protein|search|guaA], [protein|search|guaB], [protein|search|gmk]'' or inactivation of ''[protein|search|codY]'' [Pubmed|24682323,24163341]

The protein

Paralogous protein(s)

• [protein|search|SasB]

[SW|Domains]

• single ppGpp synthetase domain [Pubmed|24163341]

Structure

• [PDB|5DEC] ([SW|SasB], 39% identity, 70% similarity) [Pubmed|26460002]

Expression and Regulation

Operon

• ''sasA'' [Pubmed|11866510]

[SW|Sigma factor]

• [protein|search|SigM] [Pubmed|18179421] [protein|search|SigW] [Pubmed|11866510]

Regulation

• transcription is highly upregulated in response to lesions in late-acting teichoic acid synthesis genes ''[protein|search|tagB]'', ''[protein|search|tagD]'' and ''[protein|search|tagF]'', and also in response to cell-wall-active compounds like bacitracin or vancomycin [Pubmed|19477419]
• expression is reduced in a [protein|search|SigV] mutant [Pubmed|21926231]

Biological materials

Mutant

• GP2066 (''[SW|sasA] [SW|sasB] [SW|relA]::mls''), available in [SW|Jörg Stülke]'s lab

References

Reviews

• 27149325

Original publications

• 21926231,22950019,18670626,19447912,18067544,19477419,12207695,11866510,18179421,24163341,24489751,24687489,24682323,26460002,27875634