摘要
脱水素（Dehydrins,DHNs）是高等植物胚胎发育晚期产生的一类特异多肽,其表达累积程度与植物的发育阶段、低温、ABA和脱水信号调节等因素密切相关。为了解脱水素的结构与干旱胁迫表达累积反应,文章从六棱大麦分离到序列全长为1 767 bp的Dhn6基因,序列分析结果表明,该基因含一个92 bp内含子,90~1 759 bp为一个开放阅读框,与裸大麦Dhn6基因（GenBank登录号：AF043091）的同源性最高,达93.18%,编码523个氨基酸残基的多肽,预测蛋白质的分子量为49.68 kDa,理论等电点为8.04。结构分析发现,蛋白质具有3个螺旋区,无规则卷曲构成二级结构的主要组分,亲水氨基酸比例超过83%;三维结构预测发现,多肽链自身反向平行排列成松散的亲水索链,K-片段参与兼性？-螺旋结构域的形成,意味着该脱水素具有束缚自由水、稳定细胞膜相结构的功能。实时定量RT-PCR检测结果表明,Dhn6基因的相对表达水平在干旱处理8 h快速累积,推测DHN6在大麦对干旱胁迫的早期响应中发挥重要功能。
Dehydrins（DHNs）,proteins with protective functions encoded by the late embryogenesis abundant（LEA）,are differentially up-regulated at the transcriptional level under environmental stresses such as water deficit,salinity,and low temperature or in response to ABA.Data involving protein structure and expression of dehydrins could elucidate their func-tional roles under dehydration conditions in plants.Dhn6 gene of 1 767 bp with an intron（92 bp） in six-rowed barley,a member of LEA D11,was cloned into pMD18-T vector in the present study.It shared 93.18% identity with Hordeum vul-gare ssp.vulgare（GenBank accession： AF043091）,encoding a protein composed of 523 amino acid residues with the pre-dicted molecular weight of 49.68 kDa and the theoretical isoelectric point of 8.04.Analyses of domain and structure indi-cated that the protein was dominantly composed of 83% hydrophillic amino acid residues,with numerous imperative curls and three loosed helixes.Three-dimensional measurement revealed that the water-soluble lipid-associating protein was at-tributed to its twisted cable formed by reverse paralleled chains.Moreover,the putative amphipathic α-helices formed by K-segments might play roles in protecting membrane structure in barley.Significantly,relatively high accumulations of Dhn6 gene were detected after 8 h of water deficit by real-time quantitative RT-PCR.These results possibly suggested that the accumulation of Dhn6 gene could be critical for resistant dehydration in plants.
出处
《遗传》
CAS
CSCD
北大核心
2011年第3期270-277,共8页
Hereditas（Beijing)
基金
贵州省科学技术基金项目(编号:黔科合J字[2007]2050号)
贵州省合肥市科学技术基金项目(编号:遵市科合农字2007-05号)资助
关键词
大麦
Dhn6基因
结构预测
兼性?-螺旋结构域
干旱胁迫
barley(Hordeum vulgare L.)
Dhn6 gene
structure prediction
amphipathicα-helices
drought stress
