Structural polymorphism within the amino-terminal region of MM, NN, and MN glycoproteins (glycophorins) of the human erythrocyte membrane.
Structural polymorphism within the amino-terminal region of MM, NN, and MN glycoproteins (glycophorins) of the human erythrocyte membrane.
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人红细胞膜 MM、NN 和 MN 糖蛋白（糖蛋白）氨基末端区域的结构多态性。
DOI：
10.1073/pnas.75.6.2727
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发表时间：
1978
影响因子：
11.1
通讯作者：
A. Adamany
中科院分区：
文献类型：
--
作者：
O. Blumenfeld;A. Adamany
来自单个供体的人红细胞的MM、NN和MN糖蛋白被溴化氰切割成三个片段-A、B和C-，凝胶电泳显示这三个片段是三种抗原共有的。使用苯酚/尿素水溶液分配和凝胶过滤来定量分离肽。肽C缺乏碳水化合物和高丝氨酸，代表糖蛋白的羧基末端部分。肽A和肽B各含有一个高丝氨酸，并占糖蛋白的所有碳水化合物。来自MM、NN或MN抗原的糖肽A的肽部分由8个氨基酸残基组成，其中6个是同源的，2个根据血型而变化。糖肽A（MM）中的变体为丝氨酸和甘氨酸，A（NN）中的变体为亮氨酸和谷氨酸，A（MN）中的变体为丝氨酸、甘氨酸、亮氨酸和谷氨酸的半残基。A（MM）的氨基端为丝氨酸，A（NN）的氨基端为亮氨酸，A（MN）的氨基端为丝氨酸和亮氨酸的二分之一。每个糖肽携带两个四糖（2 NANA，1 Gal，1 GalNAc）和一个三糖（NANA，Gal，GalNAc）连接O-糖苷一个丝氨酸和两个苏氨酸确定的β-消除和亚硫酸盐加成。由于氨基端的丝氨酸残基可以被高碘酸盐氧化，所以碳水化合物单元附着在位于不变区的丝氨酸和苏氨酸上。M-N抗原被认为是等位基因的产物，其仅在纯合子中表达，而在杂合子中等摩尔地表达。
MM, NN, and MN glycoproteins of human erythrocytes from single donors were cleaved by cyanogen bromide into three fragments-A, B, and C-which, upon gel electrophoresis, appeared to be common to the three antigens. Phenol/aqueous urea partitioning and gel filtration were used to separate the peptides quantitatively. Peptide C lacked carbohydrate and homoserine and represented the carboxyl-terminal portion of the glycoproteins. Peptides A and B contained one homoserine each and accounted for all the carbohydrate of the glycoproteins. The peptide portion of glycopeptide A from MM, NN, or MN antigens consisted of eight amino acid residues, of which six were homologous and two varied according to blood type. The variants were serine and glycine in glycopeptide A(MM), leucine and glutamic acid in A(NN), and half-residues of serine, glycine, leucine, and glutamic acid in A(MN). Serine was the amino-terminal residue in A(MM), leucine in A(NN), and one half residue of serine and leucine in A(MN). Each glycopeptide carried two tetrasaccharides (2 NANA, 1 Gal, 1 GalNAc) and one trisaccharide (NANA, Gal, GalNAc) linked O-glycosidically to one serine and two threonines as determined by beta-elimination and sulfite addition. The carbohydrate units were attached to serine and threonine located in the invariant region, because the amino-terminal serine residue could be oxidized by periodate. The M-N antigens are believed to be products of allelic genes which are expressed exclusively in homozygotes and equimolarly in heterozygotes.