Warren W C, Bentle K A, Schlittler M R, Schwane A C, O'Neil J P, Bogosian G
Protiva, Monsanto Company BB3M, Chesterfield, MO 63198, USA.
Gene. 1996 Oct 3;174(2):235-8. doi: 10.1016/0378-1119(96)00086-8.
In Escherichia coli and most other microorganisms, peptide synthesis is started at methionine start codons which are read only by N-formyl-methionine-tRNA. The formyl group is normally removed from the N-terminal Met residue of the peptide by peptide deformylase (PDF). However, it has been observed that overproduction of proteins in recombinant bacteria often yields protein products which are incompletely deformylated. Certain proteins could be poor substrates for PDF and exhibit incomplete deformylation, particularly when they are overproduced. Strains of E. coli which overproduce bovine somatotropin (BST) have a significant fraction of the BST with the formyl group retained. The PDF gene was isolated and positioned into a BST production vector in such a way that the BST and PDF genes were coexpressed. In strains containing this coexpression vector, the levels of PDF were increased and formylated BST was undetectable.
在大肠杆菌和大多数其他微生物中，肽合成起始于甲硫氨酸起始密码子，这些密码子只能被N-甲酰甲硫氨酸-tRNA识别。肽通常通过肽脱甲酰基酶（PDF）从肽的N端甲硫氨酸残基上去除甲酰基。然而，已经观察到重组细菌中蛋白质的过量表达常常产生未完全脱甲酰化的蛋白质产物。某些蛋白质可能是PDF的不良底物，表现出不完全脱甲酰化，特别是当它们过量表达时。过量表达牛生长激素（BST）的大肠杆菌菌株中有很大一部分BST保留了甲酰基。PDF基因被分离出来并以BST和PDF基因共表达的方式插入到BST生产载体中。在含有这种共表达载体的菌株中，PDF水平升高，且未检测到甲酰化的BST。
