1QQY

X-RAY CRYSTAL STRUCTURE ANALYSIS OF CANINE MILK LYSOZYME (APO-TYPE)

1QQY の概要

• エントリーDOI: 10.2210/pdb1qqy/pdb
• 関連するPDBエントリー: 1cml 1dlz
• 分子名称: LYSOZYME C (2 entities in total)
• 機能のキーワード: apo-type protein, calcium binding lysozyme, enzyme, hydrolase
• 由来する生物種: Canis lupus familiaris (dog)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 14621.64

構造登録者

Koshiba, T.,Yao, M.,Tanaka, I.,Nitta, K. (登録日: 1999-06-09, 公開日: 2000-06-09, 最終更新日: 2024-10-16)

主引用文献

Koshiba, T.,Yao, M.,Kobashigawa, Y.,Demura, M.,Nakagawa, A.,Tanaka, I.,Kuwajima, K.,Nitta, K.
Structure and thermodynamics of the extraordinarily stable molten globule state of canine milk lysozyme.
Biochemistry, 39:3248-3257, 2000

PubMed Abstract: Here, we show that an unfolded intermediate of canine milk lysozyme is extraordinarily stable compared with that of the other members of the lysozyme-alpha-lactalbumin superfamily, which has been studied previously. The stability of the intermediate of this protein was investigated using calorimetry, CD spectroscopy, and NMR spectroscopy, and the results were interpreted in terms of the structure revealed by X-ray crystallography at a resolution of 1.85 A to an R-factor of 17.8%. On the basis of the results of the thermal unfolding, this protein unfolds in two clear cooperative stages, and the melting temperature from the intermediate to the unfolded states is about 20 degrees C higher than that of equine milk lysozyme. Furthermore, the (1)H NMR spectra of canine milk lysozyme at 60 degrees C, essentially 100% of which exists in the intermediate, showed that small resonance peaks that arise from ring-current shifts of aliphatic protons are still present in the upfield region from 0 to -1 ppm. The protein at this temperature (60 degrees C) and pH 4.5 has been found to bind 1-anilino-naphthalene-8-sulfonate (ANS) with enhancement of the fluorescence intensity compared with that of native and thermally unfolded states. We interpret that the extraordinarily stable intermediate is a molten globule state, and the extraordinary stabilization of the molten globule state comes from stronger protection around the C- and D-helix of the aromatic cluster region due to the His-21 residue. The conclusion helps to explain how the molten globule state acquires its structure and stability.

PubMed: 10727216
DOI: 10.1021/bi991525a

実験手法

X-RAY DIFFRACTION (1.85 Å)