Table 1 Key amino acid positions, linkers and in vitro Ca2+ response of cpFP-based Ca2+ sensors. Linker sites: linkers connecting M13 with cpFP and cpFP with calmodulin. cpFP is underlined, positions 148 and 145 are shown in bold. Data for Part A are from literature. See Methods section for the details concerning proteins purification and spectroscopy for Parts B and C
From: Single fluorescent protein-based Ca2+sensors with increased dynamic range
Sensor | Linker sites | 148 | 145 | 203 | Maximum fluorescence response to Ca2+, fold, comments |
|---|---|---|---|---|---|
Part A: previously developed sensors | |||||
Pericam | YNS H NVY---LEYN G TGDQ | H | G | Y | 3,0 × increase |
Flash-periam | YNS H NVY---LEYN G TGDQ | H | G | H | 8,0 × increase low pH stability |
Ratiometric-pericam | YNS D NVY---LEYN G TDQL | D | G | F | 10,0 × ratiometric changes |
Inverse-pericam | YNS T NVY---LEYN G TDQL | T | G | A | 5,0 × decrease |
G18 | SSL E NVY---LEYN G TRDQ | E | G | T | 4,3 × increase |
GCaMP1 | SSL E NVY---LEYN T RDQL | E | T | T | 4,3 × increase brighter than G18 due to 145T |
GCaMP1.6 | SSL E NVY---LEYN T RDQL | E | T | T | 4.9 × increase much brighter than GCaMP1 |
GCaMP2 | SSL E NVY---LEYN T RDQL | E | T | T | 5 × increase much brighter than GCaMP1.6 |
Part B: our sensors developed as a result of 145/148 positions mutagenesis | |||||
cps1 | SSL N NVY---LEYN T RDQL | N | T | F | Low increase |
cps1(A) | SSL N NVY---LEYN A RDQL | N | A | F | 1,4 × decrease |
cps1(S) | SSL N NVY---LEYN S RDQL | N | S | F | 1,5 × increase |
cps2 | SSL E NVY---LEYN T RDQL | E | T | F | 14,5 × increase |
cps2(A) | SSL E NVY---LEYN A RDQL | E | A | F | no response |
cps2(S) | SSL E NVY---LEYN S RDQL | E | S | F | 14,5 × increase |
cps4 | SSL D NVY---LEYN T RDQL | D | T | F | low increase |
cps4(S) | SSL D NVY---LEYN A RDQL | D | A | F | 7,2 × ratiometric changes |
cps4(A) | SSL D NVY---LEYN S RDQL | D | S | F | 8,0 × ratiometric changes |
Part C: Sensors developed after cpS2 random mutagenesis | |||||
Case12 | SSL E NVY---LEYN T RDQL | E | T | F | 12.0 × increase fast maturation |
Case16 | SSL E NVY---LEYN S RDQL | E | S | F | 16.5 × increase |