Table 6.

Spectrum of mutations in β-strands^a

Amino acid	Original residues	Expected residues	χ2	P value	Mutant residues	Expected residues	χ2	P value
A	39	33	0.93	3.34E-01	14	34	11.49***	6.98E-04
C	19	12	4.58*	3.24E-02	39	20	19.08***	1.26E-05
D	17	15	0.22	6.38E-01	26	22	0.56	4.54E-01
E	21	25	0.64	4.23E-01	20	20	0.01	9.36E-01
F	15	36	12.66***	3.75E-04	24	22	0.11	7.43E-01
G	44	27	10.61***	1.13E-03	27	32	0.86	3.54E-01
H	23	13	8.33**	3.90E-03	32	22	4.06*	4.38E-02
I	34	49	4.80*	2.84E-02	16	29	6.15**	1.31E-02
K	13	23	4.60*	3.20E-02	23	20	0.57	4.49E-01
L	63	66	0.10	7.48E-01	27	46	8.05**	4.56E-03
M	14	13	0.03	8.53E-01	16	13	0.90	3.43E-01
N	19	14	1.67	1.97E-01	20	22	0.27	6.05E-01
P	15	11	1.08	2.99E-01	47	34	5.27*	2.16E-02
Q	10	16	2.24	1.34E-01	20	20	0.01	9.36E-01
R	77	29	80.03***	3.69E-19	60	48	3.17	7.50E-02
S	15	23	2.88	8.98E-02	55	52	0.18	6.68E-01
T	16	35	10.20***	1.41E-03	36	34	0.16	6.88E-01
V	53	71	4.44*	3.51E-02	27	34	1.32	2.50E-01
W	16	10	3.23	7.25E-02	8	10	0.34	5.61E-01
Y	27	27	0.00	9.60E-01	13	17	0.87	3.50E-01
Sum	550	550			550	550

^aχ²-numbers in italics indicate underrepresentation and numbers in bold overrepresentation compared to random distribution based on amino acid frequencies. The results of the χ² are shown with significance level: * P < 0.05; ** P < 0.01; *** P < 0.001.