Mutations of Lysine 47 in Cyclodextrin Glycosyltransferase from Paenibacillus macerans Enhance β-Cyclodextrin Specificity

详细信息    查看全文

• 作者：Zhao-Feng Li ; Jia-Yu Zhang ; Qi Sun ; Miao Wang ; Zheng-Biao Gu ; Guo-Cheng Du ; Jing Wu ; Jian Chen
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2009
• 出版时间：September 23, 2009
• 年：2009
• 卷：57
• 期：18
• 页码：8386-8391
• 全文大小：791K
• 年卷期：v.57,no.18(September 23, 2009)
• ISSN：1520-5118

文摘

The nature of amino acid residue 47 shows a clear discrimination between the different groups of cyclodextrin glycosyltransferase (CGTase). The effects of amino acid side chain at position 47 on cyclodextrin product specificity were investigated by replacing Lys47 in the CGTase from Paenibacillus macerans strain JFB05-01 with arginine, histidine, threonine, serine, or leucine. All of the mutations reduced α-cyclodextrin-forming activity, whereas significant increases in β-cyclodextrin-forming activity were achieved. Especially, the mutations of Lys47 into threonine, serine, or leucine converted P. macerans CGTase from α-type to β/α-type. As a result, all of the mutants displayed a shift in product specificity toward the production of β-cyclodextrin. Thus, they were more suitable for the industrial production of β-cyclodextrin than the wild-type enzyme. The enhancement of β-cyclodextrin specificity might be due to weakening or removal of hydrogen-bonding interactions between the side chain of residue 47 and the bent intermediate specific for α-cyclodextrin formation.