1GLH

CATION BINDING TO A BACILLUS (1,3-1,4)-BETA-GLUCANASE. GEOMETRY, AFFINITY AND EFFECT ON PROTEIN STABILITY

1GLH の概要

• エントリーDOI: 10.2210/pdb1glh/pdb
• 分子名称: 1,3-1,4-BETA-GLUCANASE, SODIUM ION (3 entities in total)
• 機能のキーワード: hydrolase
• 由来する生物種: synthetic construct
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 23958.22

構造登録者

Keitel, T.,Heinemann, U. (登録日: 1994-11-25, 公開日: 1995-02-07, 最終更新日: 2024-10-16)

主引用文献

Keitel, T.,Meldgaard, M.,Heinemann, U.
Cation binding to a Bacillus (1,3-1,4)-beta-glucanase. Geometry, affinity and effect on protein stability
Eur.J.Biochem., 222:203-214, 1994

PubMed Abstract: The hybrid Bacillus (1,3-1,4)-beta-glucanase H(A16-M), consisting of 16 N-terminal amino acids derived from the mature form of the B. amyloliquefaciens enzyme and of 198 C-proximal amino acids from the B. macerans enzyme, binds a calcium ion at a site at its molecular surface remote from the active center [T. Keitel, O. Simon, R. Borriss & U. Heinemann (1993) Proc. Natl Acad. Sci. USA 90, 5287-5291]. X-ray diffraction analysis at 0.22-nm resolution of crystals grown in the absence of calcium and in the presence of EDTA shows this site to be occupied by a sodium ion. Whereas the calcium ion has six oxygen atoms in its coordination sphere, two of which are from water molecules, sodium is fivefold coordinated with a fifth ligand belonging to a symmetry-related protein molecule in the crystal lattice. The affinity of H(A16-M) for calcium over sodium has been determined calorimetrically. Calcium binding stabilizes the native three-dimensional structure of the protein as shown by guanidinium chloride unfolding and thermal inactivation experiments. The enhanced enzymic activity of Bacillus beta-glucanases at elevated temperatures in the presence of calcium ions is attributed to a general stabilizing effect by the cation.

PubMed: 8200344
DOI: 10.1111/j.1432-1033.1994.tb18858.x

実験手法

X-RAY DIFFRACTION (2 Å)