Cha Y, Holland S M, August J T
Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
J Biol Chem. 1990 Mar 25;265(9):5008-13.
We describe the isolation and sequencing of a cDNA encoding the mouse lysosomal membrane glycoprotein mLAMP-2 and the sequence differences that distinguish this molecule from the LAMP-1 class of proteins. An oligonucleotide probe corresponding to the NH2-terminal amino acid sequence of purified mLAMP-2 was synthesized by the polymerase chain reaction and used to screen several cDNA libraries. cDNA clones with an insert of 1,700 nucleotides were identified and sequenced. The deduced amino acid sequence of mLAMP-2 comprises a signal sequence of 25 residues and a 390-amino acid polypeptide (Mr 43,017) with the following putative domains: a large intraluminal region (residues 1-354) with 17 N-linked glycosylation sites (Asn-X-Ser/Thr), a hydrophobic transmembrane-spanning region of 24 residues (355-378), and a COOH-terminal cytoplasmic tail of 12 residues (379-390). When this sequence is compared with those of other lysosomal membrane glycoproteins, it is apparent that mouse LAMP-2 and human LAMP-2 form one homology class (LAMP-2) that is separated from the LAMP-1 class of proteins. The sequence differences in these two classes provide a basis for comparing the structure of the proteins with their biochemical and biological properties.
我们描述了编码小鼠溶酶体膜糖蛋白mLAMP - 2的cDNA的分离和测序，以及区分该分子与LAMP - 1类蛋白质的序列差异。通过聚合酶链反应合成了与纯化的mLAMP - 2的NH2末端氨基酸序列相对应的寡核苷酸探针，并用于筛选几个cDNA文库。鉴定并测序了插入片段为1700个核苷酸的cDNA克隆。mLAMP - 2推导的氨基酸序列包括一个25个残基的信号序列和一个390个氨基酸的多肽（Mr 43,017），具有以下推定结构域：一个大的腔内区域（残基1 - 354），有17个N - 连接糖基化位点（Asn - X - Ser/Thr），一个24个残基的疏水跨膜区域（355 - 378），以及一个12个残基的COOH末端细胞质尾巴（379 - 390）。当将该序列与其他溶酶体膜糖蛋白的序列进行比较时，很明显小鼠LAMP - 2和人LAMP - 2形成一个同源类（LAMP - 2），它与LAMP - 1类蛋白质分开。这两类蛋白质的序列差异为比较蛋白质结构与其生化和生物学特性提供了基础。
