2AIH

1H-NMR solution structure of a trypsin/chymotrypsin Bowman-Birk inhibitor from Lens culinaris.

2AIH の概要

• エントリーDOI: 10.2210/pdb2aih/pdb
• NMR情報: BMRB: 7078
• 分子名称: Bowman-Birk type protease inhibitor, LCTI, CHLORIDE ION (2 entities in total)
• 機能のキーワード: trypsin/chymotrypsin bowman-birk inhibitor, two-strands beta-sheet, hydrolase
• 由来する生物種: Lens culinaris (lentil)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 7861.44

構造登録者

Ragg, E.M.,Galbusera, V.,Scarafoni, A.,Negri, A.,Tedeschi, G.,Consonni, A.,Sessa, F.,Duranti, M. (登録日: 2005-07-29, 公開日: 2006-08-01, 最終更新日: 2024-11-06)

主引用文献

Ragg, E.M.,Galbusera, V.,Scarafoni, A.,Negri, A.,Tedeschi, G.,Consonni, A.,Sessa, F.,Duranti, M.
Inhibitory properties and solution structure of a potent Bowman-Birk protease inhibitor from lentil (Lens culinaris, L) seeds.
Febs J., 273:4024-4039, 2006

PubMed Abstract: Bowman-Birk serine protease inhibitors are a family of small plant proteins, whose physiological role has not been ascertained as yet, while chemopreventive anticarcinogenic properties have repeatedly been claimed. In this work we present data on the isolation of a lentil (Lens culinaris, L., var. Macrosperma) seed trypsin inhibitor (LCTI) and its functional and structural characterization. LCTI is a 7448 Da double-headed trypsin/chymotrypsin inhibitor with dissociation constants equal to 0.54 nM and 7.25 nM for the two proteases, respectively. The inhibitor is, however, hydrolysed by trypsin in a few minutes timescale, leading to a dramatic loss of its affinity for the enzyme. This is due to a substantial difference in the kon and k*on values (1.1 microM-1.s-1 vs. 0.002 microM-1.s-1), respectively, for the intact and modified inhibitor. A similar behaviour was not observed with chymotrypsin. The twenty best NMR structures concurrently showed a canonical Bowman-Birk inhibitor (BBI) conformation with two antipodal beta-hairpins containing the inhibitory domains. The tertiary structure is stabilized by ion pairs and hydrogen bonds involving the side chain and backbone of Asp10-Asp26-Arg28 and Asp36-Asp52 residues. At physiological pH, the final structure results in an asymmetric distribution of opposite charges with a negative electrostatic potential, centred on the C-terminus, and a highly positive potential, surrounding the antitryptic domain. The segment 53-55 lacks the anchoring capacity found in analogous BBIs, thus rendering the protein susceptible to hydrolysis. The inhibitory properties of LCTI, related to the simultaneous presence of two key amino acids (Gln18 and His54), render the molecule unusual within the natural Bowman-Birk inhibitor family.

PubMed: 16889634
DOI: 10.1111/j.1742-4658.2006.05406.x

実験手法

SOLUTION NMR