1K9V

Structural evidence for ammonia tunelling across the (beta-alpha)8-barrel of the imidazole glycerol phosphate synthase bienzyme complex

Summary for 1K9V

• Entry DOI: 10.2210/pdb1k9v/pdb
• Descriptor: Amidotransferase hisH, ACETIC ACID (3 entities in total)
• Functional Keywords: glutaminase, imidazole glycerol phosphate synthase, (beta-alpha)8-barrel, ammonia tunnel, transferase
• Biological source: Thermotoga maritima
• Cellular location: Cytoplasm: Q9X0C8
• Total number of polymer chains: 1
• Total formula weight: 23190.62

Authors

Douangamath, A.,Walker, M.,Beismann-Driemeyer, S.,Vega-Fernandez, M.C.,Sterner, R.,Wilmanns, M. (deposition date: 2001-10-31, release date: 2002-02-20, Last modification date: 2024-04-03)

Primary citation

Douangamath, A.,Walker, M.,Beismann-Driemeyer, S.,Vega-Fernandez, M.C.,Sterner, R.,Wilmanns, M.
Structural evidence for ammonia tunneling across the (beta alpha)(8) barrel of the imidazole glycerol phosphate synthase bienzyme complex.
Structure, 10:185-193, 2002

PubMed Abstract: Since reactive ammonia is not available under physiological conditions, glutamine is used as a source for the incorporation of nitrogen in a number of metabolic pathway intermediates. The heterodimeric ImGP synthase that links histidine and purine biosynthesis belongs to the family of glutamine amidotransferases in which the glutaminase activity is coupled with a subsequent synthase activity specific for each member of the enzyme family. Its X-ray structure from the hyperthermophile Thermotoga maritima shows that the glutaminase subunit is associated with the N-terminal face of the (beta alpha)(8) barrel cyclase subunit. The complex reveals a putative tunnel for the transfer of ammonia over a distance of 25 A. Although ammonia tunneling has been reported for glutamine amidotransferases, the ImGP synthase has evolved a novel mechanism, which extends the known functional properties of the versatile (beta alpha)(8) barrel fold.

PubMed: 11839304
DOI: 10.1016/S0969-2126(02)00702-5

Experimental method

X-RAY DIFFRACTION (2.4 Å)