Ligand Induced Folding of the First Identified CBM69 Starch Binding Domain AmyP-SBD

Author(s): Wei Zhang, Jigang Yu, Xuecheng Zhang*, Hui Peng*, Xinxin Li, Jiahai Zhang, Hongbin Sun, Xiaoming Tu.

Journal Name: Protein & Peptide Letters

Volume 25 , Issue 4 , 2018

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Abstract:

AmyP is an α-amylase which shows preferential degradation to soluble starch. In this substrate preference its Starch Binding Domain (SBD), which was recently assigned to a new Carbohydrate Binding Module (CBM) family 69, plays an important role. In the present study, the SBD of AmyP (AmyP-SBD) was recombinantly expressed, purified, and structurally characterized. Using Circular Dichroism (CD), intrinsic fluorescence, and nuclear magnetic resonance (NMR) spectroscopy, the structures of AmyP-SBD in the absence and presence of substrate analogue β-cyclodextrin were measured. The results intriguingly showed that free form AmyP-SBD is partially unfolded, like a compact molten globule, and could be induced by the ligand to fold into a relatively rigid state. Further structure determination for folded AmyP-SBD revealed a topology distinctive from those of SBDs from other CBM families. Our data indicate AmyP-SBD is a structurally novel SBD, and this may be helpful for understanding the properties of AmyP-SBD and CBM69 and elucidation of functioning mechanism of AmyP.

Keywords: Starch binding domain, molten globule, ligand induced folding, carbohydrate binding module family 69, AmyP, nuclear magnetic resonance.

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Article Details

VOLUME: 25
ISSUE: 4
Year: 2018
Page: [362 - 367]
Pages: 6
DOI: 10.2174/0929866525666180122145846
Price: $58

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