Barnes A K, Wynn C H
Department of Biochemistry and Molecular Biology, School of Biological Sciences, University of Manchester, United Kingdom.
Proteins. 1988;4(3):182-9. doi: 10.1002/prot.340040305.
Recently developed computer programs, including secondary structure and epitopic site predictions, have been used to align lysosomal proteins for maximum homology, based on conservative interchanges, and the aligned sequences have been searched for potential sites for posttranslational modification, glycosylation, and binding and catalysis of substrate. The homology and prediction of the posttranslational modification of the alpha- and beta-subunits of hexosaminidase is in good agreement with previous observations, and an explanation of the differing substrate specificities of the two subunits is advanced. We show that the striking homology between alpha-glucosidase and isomaltase is reflected in the apparent conservation of the active site in both enzymes. Nonhomologous regions have been examined in detail in a search for binding sites for glycogen and maltose, and two such sites have been tentatively identified. A highly redundant consensus sequence for the phosphorylation of mannose in lysosomal proteins, YXX(Y, W, or F), is suggested.
最近开发的计算机程序，包括二级结构和表位位点预测，已被用于比对溶酶体蛋白以实现最大程度的同源性，该比对基于保守替换，并且已对排列好的序列进行搜索，以寻找翻译后修饰、糖基化以及底物结合和催化的潜在位点。己糖胺酶α亚基和β亚基的同源性及翻译后修饰预测与先前的观察结果高度一致，并且对两个亚基不同底物特异性的解释也已提出。我们表明，α-葡萄糖苷酶和异麦芽糖酶之间显著的同源性体现在两种酶活性位点的明显保守性上。为了寻找糖原和麦芽糖的结合位点，已对非同源区域进行了详细研究，并初步确定了两个这样的位点。提出了溶酶体蛋白中甘露糖磷酸化的高度冗余共有序列YXX（Y、W或F）。
