2.1.1.B75 expressed in Escherichia coli as a His-tag fusion protein 2.1.1.B75 gene POMT7, error-prone polymerase chain reaction, expression of GST-tagged wild-type POMT7 and mutant POMT7-M1 in Escherichia coli 2.1.1.B75 expression in Escherichia coli 2.1.1.B75 expression in Streptomyces venezuelae