Elmer Aaron, Chao Wun, Grimes Howard
Program in Plant Physiology, School of Molecular Sciences, Washington State University, Pullman, WA 99164-4234, USA.
Plant Mol Biol. 2003 Jul;52(5):1089-106. doi: 10.1023/a:1025483809791.
The initial biochemical characterization of the soybean sucrose-binding protein, GmSBP, within our lab and others produced several incongruous characteristics that required a re-characterization of GmSBP via sequence homology, cell biology, immunolocalization, and semi-quantitative analysis. The GmSBP proteins share amino acid sequence homology as well as putative structural homology with globulin-like seed storage proteins. A comparison to the major soybean seed storage proteins, glycinin and beta-conglycinin established several storage protein-like characteristics for GmSBP. All three proteins were present in a prevacuolar compartment and protein storage vacuole. All three proteins increased in expression during seed development and are remobilized during germination. Quantitatively, the relative concentrations of GmSBP, beta-conglycinin (alpha/alpha' subunits), and glycinin (acidic subunits) indicated that GmSBP contributes 19-fold less to the stored nitrogen. The quantitative differences between GmSBP and glycinin may be attributed to the unconserved order and spacing of cis-acting regulatory elements present within the promoter regions. Ultimately, GmSBP is transported to the mature protein storage vacuole. The biological function of GmSBP within the protein storage vacuole remains uncertain, but its localization is a remnant of its evolutionary link to a globulin-like or vicilin-like ancestor that gave rise to the 7S family of storage proteins.
在我们实验室及其他实验室对大豆蔗糖结合蛋白GmSBP进行的初步生化特性分析产生了几个不一致的特性，这需要通过序列同源性、细胞生物学、免疫定位和半定量分析对GmSBP进行重新表征。GmSBP蛋白与球蛋白样种子贮藏蛋白具有氨基酸序列同源性以及推定的结构同源性。与大豆主要种子贮藏蛋白大豆球蛋白和β-伴大豆球蛋白的比较确定了GmSBP的几个贮藏蛋白样特性。这三种蛋白都存在于液泡前区室和蛋白贮藏液泡中。这三种蛋白在种子发育过程中表达增加，并在萌发过程中被动员。从数量上看，GmSBP、β-伴大豆球蛋白（α/α'亚基）和大豆球蛋白（酸性亚基）的相对浓度表明，GmSBP对贮藏氮的贡献少19倍。GmSBP和大豆球蛋白之间的数量差异可能归因于启动子区域内顺式作用调控元件的非保守顺序和间距。最终，GmSBP被转运到成熟的蛋白贮藏液泡中。GmSBP在蛋白贮藏液泡中的生物学功能仍不确定，但其定位是其与球蛋白样或豌豆球蛋白样祖先进化联系的残余，后者产生了7S贮藏蛋白家族。
