Kim H C, Idler W W, Kim I G, Han J H, Chung S I, Steinert P M
Laboratory of Cellular Development and Oncology, National Institute of Dental Research, National Institutes of Health, Bethesda, Maryland 20892.
J Biol Chem. 1991 Jan 5;266(1):536-9.
In order to study the expression and role of transglutaminases in the formation of the cross-linked cell envelope of human epidermis, we have used a synthetic oligonucleotide encoding the consensual active site sequence of known transglutaminase sequences. By Northern blot analysis, newborn foreskin epidermis expresses three different mRNA species of about 3.7, 3.3, and 2.9 kilobases while normal cultured epidermal keratinocytes express only the 3.7- and 2.9-kilobase species. The largest species corresponds to a known ubiquitous tissue type II or transglutaminase C activity, the smallest corresponds to a known type I or transglutaminase K activity, and the mid-sized component apparently encodes a transglutaminase E activity that has recently been shown to be expressed in terminally differentiating epidermis (Kim, H. C., Lewis, M. S., Gorman, J. L., Park, S. C., Girard, J. E., Folk, J. E. & Chung, S. I. (1990) J. Biol. Chem., in press). Using the active site oligonucleotide as a probe, we have isolated and sequenced cDNA clones encoding the transglutaminase K enzyme. The deduced complete protein sequence has 813-amino acid residues of 89.3 kDa, has a pl of 5.7, and is likely to be an essentially globular protein, which are properties expected from the partially purified enzyme. It shares 49-53% sequence homology with the other transglutaminases of known sequence, especially in regions carboxyl-terminal to the active site, and possesses sequences likely to confer its Ca2+ dependence. Interestingly, its larger size is due to extended sequences on its amino and carboxyl termini, absent on the other transglutaminases, that may define its unique properties.
为了研究转谷氨酰胺酶在人表皮交联细胞包膜形成中的表达及作用，我们使用了一种合成寡核苷酸，其编码已知转谷氨酰胺酶序列的共有活性位点序列。通过Northern印迹分析，新生儿包皮表皮表达三种不同的mRNA种类，大小约为3.7、3.3和2.9千碱基，而正常培养的表皮角质形成细胞仅表达3.7千碱基和2.9千碱基的种类。最大的种类对应于已知的普遍存在的组织II型或转谷氨酰胺酶C活性，最小的种类对应于已知的I型或转谷氨酰胺酶K活性，中等大小的组分显然编码一种转谷氨酰胺酶E活性，最近已证明其在终末分化的表皮中表达（Kim, H. C., Lewis, M. S., Gorman, J. L., Park, S. C., Girard, J. E., Folk, J. E. & Chung, S. I. (1990) J. Biol. Chem., 即将发表）。使用活性位点寡核苷酸作为探针，我们分离并测序了编码转谷氨酰胺酶K的cDNA克隆。推导的完整蛋白质序列有813个氨基酸残基，分子量为89.3 kDa，等电点为5.7，可能是一种基本呈球状的蛋白质，这些是部分纯化酶预期具有的特性。它与其他已知序列的转谷氨酰胺酶具有49 - 53%的序列同源性，尤其是在活性位点羧基末端区域，并具有可能赋予其钙依赖性的序列。有趣的是，它较大的尺寸归因于其氨基和羧基末端的延伸序列，而其他转谷氨酰胺酶没有这些序列，这些序列可能决定了它的独特特性。
