Primers used for site-directed mutagenesis.

Site-directed mutagenesis primer	Sequence (5′–3′)
K50R (forward)	CCAACTGGCACTGGGAGGTCCTTAAGTC
K50R (reverse)	GACTTAAGGACCTCCCAGTGCCAGTTGG
R263Q (forward)	GGTCTCCCTTGGCTCCCAGCAGAACCTTTG
R263Q (reverse)	CAAAGGTTCTGCTGGGAGCCAAGGGAGACC
R263K (forward)	GGTCTCCCTTGGCTCCAAGCAGAACCTTTGTG
R263K (reverse)	CACAAAGGTTCTGCTTGGAGCCAAGGGAGACC
R263E (forward)	GGTCTCCCTTGGCTCCGAGCAGAACCTTTGTG
R263E (reverse)	CACAAAGGTTCTGCTCGGAGCCAAGGGAGACC
C267S (forward)	CCCGGCAGAACCTTAGTGTAAATGAAGACGTG
C267S (reverse)	CACGTCTTCATTTACACTAAGGTTCTGCCGGG
C350S (forward)	GAGGCCCGGGCCAGTCCCTATTACGGG
C350S (reverse)	CCCGTAATAGGGACTGGCCCGGGCCTC