Foster R, Thorner J, Martin G S
Department of Biochemistry, University of California, Berkeley 94720.
J Bacteriol. 1989 Jan;171(1):272-9. doi: 10.1128/jb.171.1.272-279.1989.
The majority of the phosphotyrosine recovered from partial acid hydrolysates of 32P-labeled Escherichia coli is derived from a single prominent protein. We show here by biochemical, genetic, and immunological criteria that this protein is actually glutamine synthetase adenylylated (not phosphorylated) at tyrosine. Furthermore, all of the phosphotyrosine detectable in partial acid hydrolysates of 32P-labeled Salmonella typhimurium was eliminated in a strain deficient in both glutamine synthetase and uridylyltransferase, an enzyme which uridylylates the regulatory protein PII at a tyrosine residue. These results suggest that protein-tyrosine phosphorylation represents a rare modification in eubacterial cells.
从经32P标记的大肠杆菌的部分酸水解产物中回收的大部分磷酸酪氨酸源自一种单一的主要蛋白质。我们在此通过生化、遗传和免疫学标准表明，这种蛋白质实际上是谷氨酰胺合成酶在酪氨酸处被腺苷酰化（而非磷酸化）。此外，在谷氨酰胺合成酶和尿苷酰转移酶均缺失的鼠伤寒沙门氏菌菌株中，32P标记的鼠伤寒沙门氏菌部分酸水解产物中可检测到的所有磷酸酪氨酸都消失了，尿苷酰转移酶是一种能在酪氨酸残基处使调节蛋白PII尿苷酰化的酶。这些结果表明，蛋白质酪氨酸磷酸化在真细菌细胞中是一种罕见的修饰。
