Department of Botany, Kakatiya University, Warangal 506009, India.
Genomics Proteomics Bioinformatics. 2012 Dec;10(6):345-53. doi: 10.1016/j.gpb.2012.08.006. Epub 2012 Dec 7.
Lipid bodies store oils in the form of triacylglycerols. Oleosin, caleosin and steroleosin are unique proteins localized on the surface of lipid bodies in seed plants. This study has identified genes encoding lipid body proteins oleosin, caleosin and steroleosin in the genomes of five plants: Arabidopsis thaliana, Oryza sativa, Populus trichocarpa, Selaginella moellendorffii and Physcomitrella patens. The protein sequence alignment indicated that each oleosin protein contains a highly-conserved proline knot motif, and proline knob motif is well conserved in steroleosin proteins, while caleosin proteins possess the Dx[D/N]xDG-containing calcium-binding motifs. The identification of motifs (proline knot and knob) and conserved amino acids at active site was further supported by the sequence logos. The phylogenetic analysis revealed the presence of magnoliophyte- and bryophyte-specific subgroups. We analyzed the public microarray data for expression of oleosin, caleosin and steroleosin in Arabidopsis and rice during the vegetative and reproductive stages, or under abiotic stresses. Our results indicated that genes encoding oleosin, caleosin and steroleosin proteins were expressed predominantly in plant seeds. This work may facilitate better understanding of the members of lipid-body-membrane proteins in diverse organisms and their gene expression in model plants Arabidopsis and rice.
脂滴以三酰基甘油的形式储存油脂。油体蛋白、钙结合蛋白和甾醇结合蛋白是种子植物脂滴表面特有的蛋白质。本研究在拟南芥、水稻、杨树、卷柏和小立碗藓这 5 种植物的基因组中鉴定到了编码脂滴蛋白油体蛋白、钙结合蛋白和甾醇结合蛋白的基因。蛋白序列比对表明，每个油体蛋白都含有一个高度保守的脯氨酸结模体，甾醇结合蛋白中的脯氨酸 knob 模体高度保守，而钙结合蛋白则含有含有 Dx[D/N]xDG 的钙结合模体。序列 logo 进一步支持了活性位点模体（脯氨酸结和 knob）和保守氨基酸的鉴定。系统发育分析揭示了存在木兰植物和苔藓植物特异性亚群。我们分析了拟南芥和水稻在营养生长和生殖阶段或非生物胁迫下表达油体蛋白、钙结合蛋白和甾醇结合蛋白的公共微阵列数据。我们的结果表明，编码油体蛋白、钙结合蛋白和甾醇结合蛋白的基因主要在植物种子中表达。这项工作可能有助于更好地理解不同生物体中脂滴膜蛋白的成员及其在模式植物拟南芥和水稻中的基因表达。
