ATP-DEPENDENT PROTEIN KINASE-CATALYZED PHOSPHORYLATION OF A SERYL RESIDUE IN HPR, A PHOSPHATE CARRIER PROTEIN OF THE PHOSPHOTRANSFERASE SYSTEM IN STREPTOCOCCUS-PYOGENES
ATP-DEPENDENT PROTEIN KINASE-CATALYZED PHOSPHORYLATION OF A SERYL RESIDUE IN HPR, A PHOSPHATE CARRIER PROTEIN OF THE PHOSPHOTRANSFERASE SYSTEM IN STREPTOCOCCUS-PYOGENES
复制标题
DOI：
10.1073/pnas.80.22.6790
复制
发表时间：
1983-01-01
期刊：
影响因子：
--
通讯作者：
SAIER, MH
中科院分区：
文献类型：
--
作者：
DEUTSCHER, J;SAIER, MH
HPr是链球菌磷酸转移酶系统的磷酸载体蛋白，在需要磷酸烯醇丙酮酸（P-ePrv）、Mg 2+和酶I（P-ePrv-HPr磷酸转移酶，EC 2.7.3.9）的反应中，在单个组氨酰残基的N-1位磷酸化。除此反应外，HPr内的丝氨酰残基可以在ATP依赖性过程中磷酸化。该反应由MW约为20，000的蛋白激酶催化。在全细胞中，激酶活性受葡萄糖刺激，而在粗提物中，活性受糖酵解中间体如G-6-P、果糖1，6-二磷酸和2-磷酸甘油酸刺激。P-（Ser）-HPr不能像P-（His）-HPr那样通过酶II将其磷酸基团转移到糖上。相反，磷酸酶（MW = 70，000）水解P-（Ser）-HPr的磷酸基团。磷酸酶反应被P-ePrv和酶I的加入强烈抑制。蛋白激酶催化的磷酸化大肠杆菌中的磷酸转移酶系统的酶成分被证明。HPr中丝氨酰残基的磷酸化显然参与细菌细胞中糖转运的调节。
HPr, a phosphate carrier protein of the streptococcal phosphotransferase system, is phosphorylated at the N-1 position of a single histidyl residue in a reaction requiring phosphoenolpyruvate (P-ePrv), Mg2+ and enzyme I (P-ePrv-HPr phosphotransferase, EC 2.7.3.9). In addition to this reaction, a seryl residue within HPr can be phosphorylated in an ATP-dependent process. This reaction is catalyzed by a protein kinase with an approximate MW of 20,000. In whole cells the kinase activity is stimulated by glucose, whereas in crude extracts the activity is stimulated by glycolytic intermediates such as G-6-P, fructose 1,6-diphosphate and 2-phosphoglycerate. P-(Ser)-HPr cannot transfer its phosphate group via enzyme II to a sugar as does the P-(His)-HPr. Instead, a phosphatase (MW = 70,000) hydrolyzes the phosphate group of P-(Ser)-HPr. The phosphatase reaction is strongly inhibited by the addition of P-ePrv and enzyme I. Protein kinase-catalyzed phosphorylation of the enzyme constituents of the phosphotransferase system in Escherichia coli was demonstrated. Phosphorylation of a seryl residue in HPr is apparently involved in the regulation of sugar transport in the bacteria cell.