Table 1.

Codon optimization

Codon	E. coli Kazusa (%)	Wild STK (%)	Syn. STK (%)	Codon	E. coli Kazusa (%)	Wild STK (%)	Syn. STK (%)
Ala (A)				Asn (N)
GCA	21	24	68	AAT	45	29	67
GCT	16	64	0	AAC	55	71	33
GCG	36	0	8	Pro (P)
GCC	27	12	24	CCA	19	28	0
Cys (C)				CCT	16	39	11
TGT	45	0	0	CCG	52	22	89
TGC	55	0	0	CCC	12	11	0
Asp (D)				Gln (Q)
GAT	63	57	92	CAA	35	93	36
GAC	37	43	8	CAG	65	7	64
Glu (E)				Arg (R)
GAA	69	68	79	AGA	4	11	0
GAG	31	32	21	AGG	2	0	0
Phe (F)				CGA	6	22	0
TTT	57	81	75	CGT	39	44	67
TTC	43	19	25	CGG	10	6	0
Gly (G)				CGC	39	17	33
GGA	11	26	0	Ser (S)
GGT	34	22	68	AGT	15	14	7
GGG	15	26	0	AGC	28	32	89
GGC	40	26	32	TCA	12	25	4
His (H)				TCT	15	18	0
CAT	57	67	92	TCG	15	4	0
CAC	43	33	8	TCC	15	7	0
Ile (I)				Thr (T)
ATA	7	9	0	ACA	13	37	3
ATT	51	59	64	ACT	17	20	0
ATC	42	32	36	ACG	27	10	0
Lys (K)				ACC	44	33	97
AAA	77	79	100	Val (V)
AAG	23	21	0	GTA	15	4	0
Leu (L)				GTT	26	48	68
TTA	13	34	0	GTG	37	8	32
TTG	13	18	0	GTC	22	40	0
CTA	4	16	0	Tyr (Y)
CTT	10	13	0	TAT	57	57	91
CTG	50	11	100	TAC	43	43	8
CTC	10	8	0	Stop (TERM)
Try (W)				TAA	64	100	100
TGG	100	100	100	TAG	7	0	0
Met (M)				TGA	29	0	0
ATG	100	100	100	GC%	51	40	45

Codons with low frequency (10%) are highlighted in blue (light) and the most preferred codon for each amino acid is highlighted in gray (dark). The native Streptokinase gene has lower preferred codons with high frequency than optimized gene. For gene optimization, rare codons frequency (56.49%) were omitted completely. The GC content increased from 40% to 45%, closer to the average GC content of other highly expressed genes in E. coli Kazusa.