1B0C

EVIDENCE OF A COMMON DECAMER IN THREE CRYSTAL STRUCTURES OF BPTI, CRYSTALLIZED FROM THIOCYANATE, CHLORIDE OR SULFATE

1B0C の概要

• エントリーDOI: 10.2210/pdb1b0c/pdb
• 分子名称: PROTEIN (PANCREATIC TRYPSIN INHIBITOR) (2 entities in total)
• 機能のキーワード: bovine pancreatic trypsin inhibitor, pentameric molecule, hydrolase inhibitor
• 由来する生物種: Bos taurus (cattle)
• 細胞内の位置: Secreted: P00974
• タンパク質・核酸の鎖数: 5
• 化学式量合計: 32637.84

構造登録者

Hamiaux, C.,Prange, T.,Ries-Kautt, M.,Ducruix, A.,Lafont, S.,Astier, J.P.,Veesler, S. (登録日: 1998-11-06, 公開日: 1998-11-11, 最終更新日: 2024-10-16)

主引用文献

Hamiaux, C.,Perez, J.,Prange, T.,Veesler, S.,Ries-Kautt, M.,Vachette, P.
The BPTI decamer observed in acidic pH crystal forms pre-exists as a stable species in solution.
J.Mol.Biol., 297:697-712, 2000

PubMed Abstract: Bovine pancreatic trypsin inhibitor (BPTI) crystallizes under acidic pH conditions in the presence of thiocyanate, chloride and sulfate ions, yielding three different polymorphs in P2(1), P6(4)22 and P6(3)22 space groups, respectively. In all three crystal forms, the same decamer is found in the packing (ten BPTI molecules organized through two perpendicular 2-fold and 5-fold axes as a well-defined and compact object) in contrast to the monomeric crystal forms observed at basic pH conditions. The crystallization of BPTI under acidic conditions (pH 4.5) was investigated by small angle X-ray scattering with both under- and supersaturated BPTI solutions. Data showed the oligomerization of BPTI molecules under all investigated conditions. Accordingly, various mixtures of discrete oligomers (n=1 to 10) were considered. Calculated scattering curves were obtained using models based on the crystallographic structures, and the experimental patterns were analyzed as a linear combination of the model curves using a non-linear curve fitting procedure. The results, confirmed by gel filtration experiments, unambiguously demonstrate the co-existence of two different BPTI particles in solution: a monomer and a decamer, with no evidence of any other intermediates. Moreover, using both approaches, the fraction of decamers was found to increase with increasing salt concentration, even beyond the solubility curve. We therefore propose that at acidic pH, BPTI crystallizes following a two step process: decamers are first built in under- and supersaturated solutions, upon which crystal growth proceeds by decamer stacking. Indeed, those BPTI crystals should best be described as "BPTI decamer" crystals.

PubMed: 10731422
DOI: 10.1006/jmbi.2000.3584

実験手法

X-RAY DIFFRACTION (2.8 Å)