Armugam A, Earnest L, Chung M C, Gopalakrishnakone P, Tan C H, Tan N H, Jeyaseelan K
Department of Biochemistry, University of Malaya, Kuala Lumpur, Malaysia.
Toxicon. 1997 Jan;35(1):27-37. doi: 10.1016/s0041-0101(96)00071-2.
cDNAs encoding three phospholipase A2 (PLA2) isoforms in Naja naja sputatrix were cloned and characterized. One of them encoded an acidic PLA2 (APLA) while the others encoded neutral PLA2 (NPLA-1 and NPLA-2). The specific characteristics of APLA and NPLA were attributed to mutations at nt139 and nt328 from G to C and G to A, respectively, resulting in amino acid substitutions from Asp20 and 83 in APLA to His20 and Asn83 in NPLA. Amino acid sequencing of purified protein also showed the presence of this Asp20 and His20 in APLA and NPLA, respectively. The cDNA encoding one of the PLA2 (NAJPLA-2A), when expressed in Escherichia coli, yielded a protein that exhibited PLA2 activity.
克隆并鉴定了眼镜蛇（Naja naja sputatrix）中编码三种磷脂酶A2（PLA2）同工型的cDNA。其中一种编码酸性PLA2（APLA），而其他两种编码中性PLA2（NPLA-1和NPLA-2）。APLA和NPLA的特异性特征分别归因于第139位核苷酸从G突变为C以及第328位核苷酸从G突变为A，导致APLA中的天冬氨酸20和83分别替换为NPLA中的组氨酸20和天冬酰胺83。纯化蛋白的氨基酸测序也显示APLA和NPLA中分别存在天冬氨酸20和组氨酸20。编码PLA2之一（NAJPLA-2A）的cDNA在大肠杆菌中表达时，产生了一种具有PLA2活性的蛋白质。
