1B9O

HUMAN ALPHA-LACTALBUMIN, LOW TEMPERATURE FORM

1B9O の概要

• エントリーDOI: 10.2210/pdb1b9o/pdb
• 分子名称: PROTEIN (ALPHA-LACTALBUMIN), CALCIUM ION (3 entities in total)
• 機能のキーワード: calcium-binding protein, high resolution
• 由来する生物種: Homo sapiens (human)
• 細胞内の位置: Secreted: P00709
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 14134.19

構造登録者

Harata, K.,Abe, Y.,Muraki, M. (登録日: 1999-02-14, 公開日: 1999-03-31, 最終更新日: 2024-10-30)

主引用文献

Harata, K.,Abe, Y.,Muraki, M.
Crystallographic evaluation of internal motion of human alpha-lactalbumin refined by full-matrix least-squares method.
J.Mol.Biol., 287:347-358, 1999

PubMed Abstract: The low temperature form of human alpha-lactalbumin (HAL) was crystallized from a 2H2O solution and its structure was refined to the R value of 0.119 at 1.15 A resolution by the full-matrix least-squares method. Average estimated standard deviations of atomic parameters for non-hydrogen atoms were 0.038 A for coordinates and 0.044 A2 for anisotropic temperature factors (Uij). The magnitude of equivalent isotropic temperature factors (Ueqv) was highly correlated with the distance from the molecular centroid and fitted to a quadratic equation as a function of atomic coordinates. The atomic thermal motion was rather isotropic in the core region and the anisotropy increased towards the molecular surface. The statistical analysis revealed the out-of-plane motion of main-chain oxygen atoms, indicating that peptide groups are in rotational vibration around a Calpha.Calpha axis. The TLS model, which describes the rigid-body motion in terms of translation, libration, and screw motions, was adopted for the evaluation of the molecular motion and the TLS parameters were determined by the least-squares fit to Uij. The reproduced Ueqvcal from the TLS parameters was in fair agreement with observed Ueqv, but differences were found in regions of residues, 5-22, 44-48, 70-75, and 121-123, where Ueqv was larger than Ueqvcal because of large local motions. To evaluate the internal motion of HAL, the contribution of the rigid-body motion was determined to be 42.4 % of Ueqv in magnitude, which was the highest estimation to satisfy the condition that the Uijint tensors of the internal motion have positive eigen values. The internal motion represented with atomic thermal ellipsoids clearly showed local motions different from those observed in chicken-type lysozymes which have a backbone structure very similar to HAL. The result indicates that the internal motion is closely related to biological function of proteins.

PubMed: 10080897
DOI: 10.1006/jmbi.1999.2598

実験手法

X-RAY DIFFRACTION (1.15 Å)