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	PROSITE documentation PDOC00152

Tryptophan synthase (EC 4.2.1.20) catalyzes the last step in the biosynthesis of tryptophan: the conversion of indoleglycerol phosphate and serine, to tryptophan and glyceraldehyde 3-phosphate [1,2]. It has two functional domains: one for the aldol cleavage of indoleglycerol phosphate to indole and glyceraldehyde 3-phosphate and the other for the synthesis of tryptophan from indole and serine. In bacteria and plants [3], each domain is found on a separate subunit (α and β chains), while in fungi the two domains are fused together on a single multifunctional protein.

The β chain of the enzyme requires pyridoxal-phosphate as a cofactor. The pyridoxal-phosphate group is attached to a lysine residue. The region around this lysine residue also contains two histidine residues which are part of the pyridoxal-phosphate binding site. The signature pattern for the tryptophan synthase β chain is derived from that conserved region.

Last update:

December 2004 / Pattern and text revised.

PROSITE method (with tools and information) covered by this documentation:

TRP_SYNTHASE_BETA, PS00168; Tryptophan synthase beta chain pyridoxal-phosphate attachment site  (PATTERN)

• Consensus pattern:
  [LIVMYAHQ]-x-[HPYNVF]-x-G-[STA]-H-K-x-N-x(2)-[LIVM]-x-[QEH]
  K is the pyridoxal-P attachment site
• Sequences in UniProtKB/Swiss-Prot known to belong to this class: 456
  • detected by PS00168: 451 (true positives)
  • undetected by PS00168: 5 (2 false negatives and 3 'partials')
• Other sequence(s) in UniProtKB/Swiss-Prot detected by PS00168:
  NONE.
• Retrieve an alignment of UniProtKB/Swiss-Prot true positive hits:
  Clustal format, color, condensed view  /  Clustal format, color  /  Clustal format, plain text  /  Fasta format
• Retrieve the sequence logo from the alignment
• Taxonomic distribution of all UniProtKB (Swiss-Prot + TrEMBL) entries matching PS00168
• Retrieve a list of all UniProtKB (Swiss-Prot + TrEMBL) entries matching PS00168
• Scan UniProtKB (Swiss-Prot and/or TrEMBL) entries against PS00168
• View ligand binding statistics of PS00168
• Matching PDB structures: 1A50 1A5A 1A5B 1A5S ... [ALL]

1	Authors	Crawford I.P.
	Title	Evolution of a biosynthetic pathway: the tryptophan paradigm.
	Source	Annu. Rev. Microbiol. 43:567-600(1989).
	PubMed ID	2679363
	DOI	10.1146/annurev.mi.43.100189.003031

2	Authors	Hyde C.C., Miles E.W.
	Title	The tryptophan synthase multienzyme complex: exploring structure-function relationships with X-ray crystallography and mutagenesis.
	Source	Biotechnology (N.Y.) 8:27-32(1990).
	PubMed ID	1366510

3	Authors	Berlyn M.B., Last R.L., Fink G.R.
	Title	A gene encoding the tryptophan synthase beta subunit of Arabidopsis thaliana.
	Source	Proc. Natl. Acad. Sci. U.S.A. 86:4604-4608(1989).
	PubMed ID	2734310

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