PDBsum entry 1bw0

Transferase

PDB id: 1bw0

Contents

Protein chains

412 a.a. *

Waters ×118

* Residue conservation analysis

References listed in PDB file

Key reference

• Title: Crystal structure of trypanosoma cruzi tyrosine aminotransferase: substrate specificity is influenced by cofactor binding mode.
• Authors: W.Blankenfeldt, C.Nowicki, M.Montemartini-Kalisz, H.M.Kalisz, H.J.Hecht.
• Ref.: Protein Sci, 1999, 8, 2406-2417. [DOI no: 10.1110/ps.8.11.2406]
• PubMed id: 10595543

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.

Secondary reference #1

• Title: Crystallization and preliminary X-Ray analysis of tyrosine aminotransferase from trypanosoma cruzi epimastigotes.
• Authors: C.Nowicki, M.Montemartini, G.R.Hunter, W.Blankenfeldt, H.M.Kalisz, H.J.Hecht.
• Ref.: Acta Crystallogr D Biol Crystallogr, 1998, 54, 105-107. [DOI no: 10.1107/S0907444997008019]
• PubMed id: 9761826

Figure 1.
Figure 1 Section = 180° of the self-rotation function calculated for the TAT native data set collected at 285 K. Using 45° as integration radius and data in the resolution shell 20.0-4.0 Å the non-crystallographic twofold axis is indicated by a maximum at = 65°, = 169° with a height of 6 . The section is contoured starting at 2 in steps of 1 .

The above figure is reproduced from the cited reference with permission from the IUCr

Secondary reference #2

• Title: Aromatic amino acid transamination and methionine recycling in trypanosomatids.
• Authors: B.J.Berger, W.W.Dai, H.Wang, R.E.Stark, A.Cerami.
• Ref.: Proc Natl Acad Sci U S A, 1996, 93, 4126-4130.
• PubMed id: 8633027

Secondary reference #3

• Title: Production of aromatic alpha-Hydroxyacids by epimastigotes of trypanosoma cruzi, And its possible role in nadh reoxidation.
• Authors: M.Montemartini, J.A.Santomé, J.J.Cazzulo, C.Nowicki.
• Ref.: Fems Microbiol Lett, 1994, 118, 89-92. [DOI no: 10.1016/0378-1097(94)90601-7]
• PubMed id: 8013884