1MBQ

Anionic Trypsin from Pacific Chum Salmon

1MBQ の概要

• エントリーDOI: 10.2210/pdb1mbq/pdb
• 関連するPDBエントリー: 2TBS
• 分子名称: Trypsin, CALCIUM ION, BENZAMIDINE, ... (4 entities in total)
• 機能のキーワード: psychrophilic enzymes, proteinase-catalyzed peptide coupling, hydrolase
• 由来する生物種: Oncorhynchus keta (chum salmon)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 23763.74

構造登録者

Toyota, E.,Ng, K.K.S.,Kuninaga, S.,Sekizaki, H.,Itoh, K.,Tanizawa, K.,James, M.N.G. (登録日: 2002-08-03, 公開日: 2002-12-11, 最終更新日: 2024-10-30)

主引用文献

Toyota, E.,Ng, K.K.S.,Kuninaga, S.,Sekizaki, H.,Itoh, K.,Tanizawa, K.,James, M.N.G.
Crystal Structure and Nucleotide Sequence of an Anionic Trypsin from Chum Salmon (Oncorhynchus keta) in Comparison with Atlantic Salmon (Salmo salar) and Bovine Trypsin
J.Mol.Biol., 324:391-397, 2002

PubMed Abstract: The nucleotide sequence and crystal structure of chum salmon trypsin (CST) are now reported. The cDNA isolated from the pyloric caeca of chum salmon encodes 222 amino acid residues, the same number of residues as the anionic Atlantic salmon trypsin (AST), but one residue less than bovine beta-trypsin (BT). The net charge on CST determined from the sum of all charged amino acid side-chains is -3. There are 79 sequence differences between CST and BT, but only seven sequence differences between CST and AST. Anionic CST isolated from pyloric caeca has also been purified and crystallized; the structure of the CST-benzamidine complex has been determined to 1.8A resolution. The overall tertiary structure of CST is similar to that of AST and BT, but some differences are observed among the three trypsins. The most striking difference is at the C terminus of CST, where the expected last two residues are absent. The absence of these residues likely increases the flexibility of CST by the loss of important interactions between the N and C-terminal domains. Similarly, the lack of Tyr151 in CST (when compared with BT) allows more space for Gln192 in the active site thereby increasing substrate accessibility to the binding pocket. Lys152 in CST also adopts the important role of stabilizing the loop from residue 142 to 153. These observations on CST provide a complementary view of a second cold-adapted trypsin, which in comparison with the structures of AST and BT, suggest a structural basis for differences in enzymatic activity between enzymes from cold-adapted species and mammals.

PubMed: 12445776
DOI: 10.1016/S0022-2836(02)01097-5

実験手法

X-RAY DIFFRACTION (1.8 Å)