1BW0

CRYSTAL STRUCTURE OF TYROSINE AMINOTRANSFERASE FROM TRYPANOSOMA CRUZI

1BW0 の概要

• エントリーDOI: 10.2210/pdb1bw0/pdb
• 分子名称: PROTEIN (TYROSINE AMINOTRANSFERASE) (2 entities in total)
• 機能のキーワード: tyrosine catabolism, transferase, aminotransferase, pyridoxal-5'-phosphate, plp
• 由来する生物種: Trypanosoma cruzi
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 92899.98

構造登録者

Blankenfeldt, W.,Montemartini, M.,Hunter, G.R.,Kalisz, H.M.,Nowicki, C.,Hecht, H.J. (登録日: 1998-09-28, 公開日: 1999-09-27, 最終更新日: 2023-11-15)

主引用文献

Blankenfeldt, W.,Nowicki, C.,Montemartini-Kalisz, M.,Kalisz, H.M.,Hecht, H.J.
Crystal structure of Trypanosoma cruzi tyrosine aminotransferase: substrate specificity is influenced by cofactor binding mode.
Protein Sci., 8:2406-2417, 1999

PubMed Abstract: The crystal structure of tyrosine aminotransferase (TAT) from the parasitic protozoan Trypanosoma cruzi, which belongs to the aminotransferase subfamily Igamma, has been determined at 2.5 A resolution with the R-value R = 15.1%. T. cruzi TAT shares less than 15% sequence identity with aminotransferases of subfamily Ialpha but shows only two larger topological differences to the aspartate aminotransferases (AspATs). First, TAT contains a loop protruding from the enzyme surface in the larger cofactor-binding domain, where the AspATs have a kinked alpha-helix. Second, in the smaller substrate-binding domain, TAT has a four-stranded antiparallel beta-sheet instead of the two-stranded beta-sheet in the AspATs. The position of the aromatic ring of the pyridoxal-5'-phosphate cofactor is very similar to the AspATs but the phosphate group, in contrast, is closer to the substrate-binding site with one of its oxygen atoms pointing toward the substrate. Differences in substrate specificities of T. cruzi TAT and subfamily Ialpha aminotransferases can be attributed by modeling of substrate complexes mainly to this different position of the cofactor-phosphate group. Absence of the arginine, which in the AspATs fixes the substrate side-chain carboxylate group by a salt bridge, contributes to the inability of T. cruzi TAT to transaminate acidic amino acids. The preference of TAT for tyrosine is probably related to the ability of Asn17 in TAT to form a hydrogen bond to the tyrosine side-chain hydroxyl group.

PubMed: 10595543

実験手法

X-RAY DIFFRACTION (2.5 Å)