Aiyappa P S, Lampen J O
Biochim Biophys Acta. 1976 Oct 19;448(3):401-10. doi: 10.1016/0005-2736(76)90296-0.
The membrane-bound penicillinase of Bacillus licheniformis 749/C is a phospholipoprotein that differs from the hydrophilic exoenzyme in that its polypeptide chain carries an additional 25 residues (mostly hydrophilic) with phosphatidylserine as the NH2-terminus. To determine if other phospholipoproteins are present in the plasma membrane, the penicillinase-inducible strain 749 was grown without inducer in the presence of [2-(3)H] glycerol. Electrophoretic separation of the membrane proteins (after removal of free lipids) showed an association of 3H-activity with certain of the proteins which could not be broken by lipid solvents and strongly denaturing conditions. Pronase digestion of the membrane proteins (after solvent extraction) released phosphatidylserine, thus indicating the covalent linkage of protein and phospholipid. Treatment of the isolated membranes with trypsin solubilized the protein portion of some of the phospholipoproteins (as with penicillinase), but not the 3H-labelled fragment. Penicillinase should be considered as the first observed example of a group of phosphatidylserine-containing proteins present in the plasma membrane of B. licheniformis 749 and 749/C.
地衣芽孢杆菌749/C的膜结合青霉素酶是一种磷脂蛋白，它与亲水性胞外酶的不同之处在于其多肽链带有额外的25个残基（大多为亲水性），且以磷脂酰丝氨酸作为氨基末端。为了确定质膜中是否存在其他磷脂蛋白，青霉素酶诱导型菌株749在无诱导剂的情况下于[2-(3)H]甘油存在时培养。对膜蛋白进行电泳分离（去除游离脂质后）显示，3H活性与某些不能被脂质溶剂和强变性条件破坏的蛋白质相关联。对膜蛋白进行蛋白酶消化（溶剂萃取后）释放出磷脂酰丝氨酸，从而表明蛋白质与磷脂存在共价连接。用胰蛋白酶处理分离的膜可溶解一些磷脂蛋白的蛋白质部分（如青霉素酶），但不能溶解3H标记的片段。青霉素酶应被视为在地衣芽孢杆菌749和749/C质膜中存在的一组含磷脂酰丝氨酸蛋白质中首个被观察到的例子。
