COMPLETE AMINO-ACID-SEQUENCE AND HOMOLOGIES OF HUMAN-ERYTHROCYTE MEMBRANE-PROTEIN BAND-4.2
COMPLETE AMINO-ACID-SEQUENCE AND HOMOLOGIES OF HUMAN-ERYTHROCYTE MEMBRANE-PROTEIN BAND-4.2
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DOI：
10.1073/pnas.87.2.613
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发表时间：
1990-01-01
影响因子：
11.1
通讯作者：
COHEN, CM
中科院分区：
文献类型：
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作者：
KORSGREN, C;LAWLER, J;COHEN, CM
人红细胞带4.2的完整氨基酸序列来自全长2.35-丝氨酸蛋白酶（kb）cDNA的核苷酸序列。该2.35-kb cDNA是从表达载体Gt 11中制备的人网织红细胞cDNA文库中分离的。在2348个碱基对（bp）中，2073 bp编码691个氨基酸，代表76.9 kDa（SDS/PAGE分子量为72 kDa）。人网织红细胞总RNA的RNA印迹分析给出了条带4.2和2.4 kb的信息大小。条带4.2的氨基酸序列与两种密切相关的Ca 2+依赖性交联蛋白，豚鼠肝转氨酶（蛋白-谷氨酰胺γ-氨基转移酶）具有同源性。谷氨酰转移酶;蛋白质-谷氨酰胺：胺γ-谷氨酰转移酶，EC 2.3.2.13）（在446个氨基酸重叠中有32%的同一性）和人凝血因子XIII的α亚基（在639个氨基酸重叠中有27%的同一性），人凝血因子XIII是一种形成分子间γ-谷氨酰转移酶。谷氨酰-ε-纤维蛋白分子之间的赖氨酸键。同一性最高的区域包括条带4.2的一段49个氨基酸，分别与豚鼠肝转氨酶和因子XIII的a亚基有69%和51%的同一性，在含有这些酶的活性位点的区域内。值得注意的是，在转氨酶活性位点Gly-Gln-Cys-Trp-瓦尔的5个连续共有残基内，条带4.2具有丙氨酸取代半胱氨酸（其显然是活性所必需的）。与这种活性位点取代一致，含有条带4.2的红细胞膜或由内而外的resicles通过两种类型的体外测定显示没有转氨酶活性的证据。
The complete amino acid sequence for human erythrocyte band 4.2 has been derived from the nucleotide sequence of a full-length 2.35-kilobase (kb) cDNA. The 2.35-kb cDNA was isolated from a humamn reticulocyte cDNA library made in the expression, vector .lambda.gt11. Of the 2348 base pairs (bp), 2073 bp encode 691 amino acids representing 76.9 kDa (the SDS/PAGE molecular mass is 72 kDa). RNA blot analysis of human reticulocyte total RNA gives a message size for band 4.2 and 2.4 kb. The amino acid sequence of band 4.2 has homology with two closely related Ca2+-dependent cross-linking proteins, guinea pig liver transglutaminase (protein-glutamine .gamma.-glutamyltransferase; protein-glutamine:amine .gamma.-glutamyltransferase, EC 2.3.2.13) (32% identity in a 446-amino acid overlap) and the a subunit of human coagulation factor XIII (27% identity in a 639-amino acid overlap), a transglutaminase that forms intermolecular .gamma.-glutamyl-.epsilon.-lysine bonds between fibrin molecules. The region of greatest identity includes a 49-amino acid stretch of band 4.2, which is 69% and 51% identical with guinea pig liver transglutaminase and the a subunit of factor XIII, respectively, within the regions that contain the active sites of these enzymes. significantly, within the five contiguous consensus residues of the transglutaminase active site, Gly-Gln-Cys-Trp-Val, band 4.2 has an alanine substituted for cysteine (which is apparently essential for activity). Consistent with this active site substitution, erythrocyte membranes or inside-out resicles, which contain band 4.2, showed no evidence of transglutaminase activity by two types of in vitro assay.