The SCD Gene Cloning In S.maindroina And Bioinformatics Analysis

Strearyl coenzyme A desaturation enzyme is the key enzyme of fatty aciddesaturation, and it is also the important source of energy in the body for maintainingmembrane fluidity with polyunsaturated fatty acids (PUFA) which is the importantcomponent in the membrane. We took the Sepiella maindroni as the main material inthis experiment. In this paper, a1513bp full-length cDNA of SCD gene from S.maindroni was obtained with RT-PCR and rapid amplification of cDNA ends (RACE)techniques. It consisited of261bp5′untranslated region (UTR),921bp open readingframe (ORF), and349bp3′UTR. To study the S. maindroni SCD gene deeply，variousbioinformatic methods such as BLASTn, ORF Finder, ProtScale, ScanProsite andTmpred Seiver were used to analyse and predict the feature and possible functions ofthe SCDgene. Blastn analysis showed that S. maindroni SCD shared high similaritywith Octopus vulgaris, and their homology was up to76%. Clustalx analysis showedthat S. maindroni SCD protein sequence homology was up to91%with the proteinsequence of Octopus vulgaris, which revealed that the structure was relativelyconservative in molluscs. And S. maindroni SCD protein sequence homologyalignment was more than50%of similarity with other mollusks which showed thatSCD molecular evolutionary classification was old which might be evolved from acommon ancestor. SCD gene phylogenetic tree analysis of different sepecies found thatit had recent relationship with Octopus vulgaris, little farther with fish and relatedfarthest with other mammals. TMHMM server v.2.0software online prediction showedthat SCD gene contained four transmembraneregions which located at50-100and200-250amino acids, explaining SCD protein for typical transmembrane protein.SignalP4.0online tools to predict SCD precursor protein result showed that it didn’tcontain a signal peptide site. PSORT software speculated that the most likely targetprotein functional area was the endoplasmic reticulum. Through ProtParam, ProtScalePredict Protein online services and software to forecast the SCD protein showed thatthe theoretical molecular weight was34922.4Da, and theoretical isoelectric point was8.95which alanine and leucine content was more higher，reaching7.5%and10.5%,respectively，nonpolar amino acid accounted for25%，polar amino acid accounted for30%; ProtScale software analysis showed that SCD hydrophilic protein index was0.061showing that it was the hydrophobic protein. SCD contained rich spiral structure,45.1%screw,9.48%extentsion chain and45.52%random curl. S. maindroni SCD gene cloning and related analysis were of great significance to explore mollusks fattyacid metabolism related genes in the biological and regulation mechanisms, alsoprovided the scientific basis on molecular level in S. maindroni thoroughbred breedingand artifical breeding.