Imaging and Measuring Single-Molecule Interaction between a Carbohydrate-Binding Module and Natural Plant Cell Wall Cellulose

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• 作者：Mengmeng Zhang ; Sheng-Cheng Wu ; Wen Zhou ; Bingqian Xu
• 刊名：The Journal of Physical Chemistry B
• 出版年：2012
• 出版时间：August 23, 2012
• 年：2012
• 卷：116
• 期：33
• 页码：9949-9956
• 全文大小：481K
• 年卷期：v.116,no.33(August 23, 2012)
• ISSN：1520-5207

文摘

The affinitive interaction between a carbohydrate-binding module (CBM3a) and natural crystalline cellulose was visualized and measured at the single-molecule level. Noncontact high resolution imaging by atomic force microscopy (AFM) was used to follow the binding process, in real time, of CBM3a-functionalized 6 nm gold nanoparticles (GNPs) to the cell wall polymers on poplar stem sections. The GNP鈥揅BM3a complexes were found to bind to the cellulose surface, closely aligning along the cellulose fibril axis. The binding details were further confirmed and studied by single-molecule recognition imaging and AFM single-molecule dynamic force spectroscopy (SMDFS) using a CBM3a-functionalized AFM tip. The unbinding force was measured to be 44.96 卤 18.80 pN under a loading rate of 67.2 nN/s. This research provides a radical method for the study of single-molecule affinity between CBM and cellulose that is critical to the engineering of novel cellulolytic enzymes.