Table 3. Screening of circular-permutated mKate variants in E.coli.

Variant *	Colony brightness 24 h at 37°C (% of mKate)	Colony brightness 72 h at 2–8°C (% of mKate)
mKate	100	100
pRSET-A	0	0
cp139-138a	0	0
cp140-139a	0	0
cp141-140a	0	0
cp144-143a	0	0
Loop 7-8 region and flanking sites
cp148-147	0	0
cp149-148	1.1	32.3
cp150-149	0.2	11.7
cp151-150b	7.5	28.4
cp152-151	5.1	21.4
cp153-152	2.9	20.8
cp154-153	10.9	19.4
cp155-154	0	0
cp156-155	0	0
Loop 8–9 region and flanking sites
cp164-163	0	0
cp165-164	1.9	13.2
cp166-165	10.2	24.7
cp167-166c	6.6	21.6
cp168-167	3.6	22.2
cp169-168	1.6	16.3
cp170-169	0	0
Loop 9–10 region and flanking sites
cp180-179	0	0
cp181-180	0	0
cp182-181	11.5	12.6
cp183-182	23.7	30.0
cp184-183	18.7	28.4
cp185-184	9.7	17.5
cp186-185	21.2	27.7
cp187-186	26.7	30.8
cp188-187	9.9	19.7
cp189-188d	33.9	55.2
cp190-189	12.1	18.3
cp191-190	8.3	15
cp192-191	0.4	6
cp193-192	0	0
cp194-193	0	0

^*The circularly permuted variants are labeled with the new amino and carboxy termini.

^aAlign to cp-EGFP in GCaMP2.

^bAligns to cp-mCherry^159-158.

^cAligns to cp-mCherry ^175-174.

^dAligns to cp-mCherry^194-193.