烟草纤维素合成酶1(CESA1)蛋白结构比较

Protein Structure Comparison of Cellulose Synthase 1(CESA1) in Tobacco

纤维素合成酶1(cellulose synthase 1,CESA1)可催化合成纤维素,参与植物细胞壁的生物合成过程.烟草品种WS38的CESA1基因尚未被克隆,烟草属间的CESA1结构特征差异未知.本研究通过RT-PCR方法克隆了烟草WS38 CESA1基因的cDNA;依据其推导的编码氨基酸序列,利用生物信息学方法比较了3个烟草间的CESA1蛋白结构特征.结果表明,烟草WS38 CESA1基因cDNA全长3276 bp,编码1091个氨基酸,与烟草SR1以及花烟草(Nicotiana alata)CESA1序列同源性超过98%.3个烟草的CESA1一级结构、二级结构以及三级结构比较相似,但也存在一定的差异.其中烟草WS38和SR1之间的差异性较WS38与花烟草(Nicotiana alata)之间的小;3个烟草CESA1典型结构特征均相同,N端都具有1个锌指结构,均具有8个跨膜结构域,磷酸化位点修饰均相同,均具有蛋白激酶活性.此外,3个烟草的CESA1均定位在细胞质膜上,它们的蛋白亲缘关系相近,功能应较为一致.

Cellulose synthase 1 catalyzes the synthesis of cellulose,which involved in the process of plant cell wall biosynthesis.The CESA1 gene of Nicotiana tabacum WS38 had not been cloned.Furthermore,the CESA1 structure characteristics differences among Nicotiana still unclear.In this study,the CESA1 gene cDNA from Nicotiana WS38 was cloned via RT-PCR method.The CESA1 structure characteristics differences among three Nicotiana varieties were also analyzed according to the sequences of deduced amino acid using bioinformatics methods.Sequence analysis demonstrated that the length of CEAS1 gene cDNA of WS38 coding region was 3276 bp,which encoded a 1091 amino acids polypeptide and shared 98%homologies with Nicotiana tabacum SR1 and Nicotianaalata.Information analysis showed that the first,secondary and tertiary structures of CESA1 were similar,but some differences still existed among three Nicotiana varieties.There are smaller differences in the CESA1 structures between WS38 and SR1 than WS38 and Nicotiana alata.Moreover,the typical structural features of CESA1 among three Nicotiana varieties were the same.A zinc fingers and eight transmembrane domains were found in CESA1 of three Nicotiana varieties.The phosphorylation sites in CESA1 were also unanimous.In addition,the CESA1 of all the Nicotiana varieties had the protein kinase activities.Besides,three CESA1 located in the plasma membrane,shared the high evolutionary relationships.Therefore,we deduced that the functions of three CESA1 were similar.