1UKO

Crystal structure of soybean beta-amylase mutant substituted at surface region

1UKO の概要

• エントリーDOI: 10.2210/pdb1uko/pdb
• 関連するPDBエントリー: 1BFN 1BYA 1BYB 1BYC 1BYD 1FA2 1UKP
• 分子名称: Beta-amylase, SULFATE ION (3 entities in total)
• 機能のキーワード: (alpha/beta)8 barrel, hydrolase
• 由来する生物種: Glycine max (soybean)
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 226606.59

構造登録者

Kang, Y.N.,Adachi, M.,Mikami, B.,Utsumi, S. (登録日: 2003-08-30, 公開日: 2004-02-10, 最終更新日: 2023-10-25)

主引用文献

Kang, Y.N.,Adachi, M.,Mikami, B.,Utsumi, S.
Change in the crystal packing of soybean beta-amylase mutants substituted at a few surface amino acid residues
Protein Eng., 16:809-817, 2003

PubMed Abstract: In spite of the high similarity of amino acid sequence and three-dimensional structure between soybean beta-amylase (SBA) and sweet potato beta-amylase (SPB), their quaternary structure is quite different, being a monomer in SBA and a tetramer in SPB. Because most of the differences in amino acid sequences are found in the surface region, we tested the tetramerization of SBA by examining mutations of residues located at the surface. We designed the SBA tetramer using the SPB tetramer structure as a model and calculating the change of accessible surface area (DeltaASA) for each residue in order to select sites for the mutation. Two different mutant genes encoding SB3 (D374Y/L481R/P487D) and SB4 (K462S added to SB3), were constructed for expression in Escherichia coli and the recombinant proteins were purified. They existed as a monomer in solution, but gave completely different crystals from the native SBA. The asymmetric unit of the mutants contains four molecules, while that of native SBA contains one. The interactions of the created interfaces revealed that there were more intermolecular interactions in the SB3 than in the SB4 tetramer. The substituted charged residues on the surface are involved in interactions with adjacent molecules in a different way, forming a new crystal packing pattern.

PubMed: 14631070
DOI: 10.1093/protein/gzg109

実験手法

X-RAY DIFFRACTION (2.1 Å)