TY - JOUR
T1 - Cyanotryptophans as Novel Fluorescent Probes for Studying Protein Conformational Changes and DNA-Protein Interaction
AU - Talukder, Poulami
AU - Chen, Shengxi
AU - Roy, Basab
AU - Yakovchuk, Petro
AU - Spiering, Michelle M.
AU - Alam, Mohammad P.
AU - Madathil, Manikandadas M.
AU - Bhattacharya, Chandrabali
AU - Benkovic, Stephen J.
AU - Hecht, Sidney M.
N1 - Funding Information:
This study was supported by Grant GM 092946 from the National Institute of General Medical Sciences, National Institutes of Health.
Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/12/29
Y1 - 2015/12/29
N2 - Described herein are the syntheses and photophysical characterization of three novel cyanotryptophans, and their efficient incorporation into proteins as fluorescent probes. Photophysical characteristics indicated that each was significantly brighter and red-shifted in fluorescence emission relative to tryptophan. Each analogue was used to activate a suppressor tRNA transcript and was incorporated with good efficiency into two different positions (Trp22 and Trp74) of Escherichia coli dihydrofolate reductase (ecDHFR). The Trp analogues could be monitored selectively in the presence of multiple native Trp residues in DHFR. 6-CNTrp (A) formed an efficient Förster resonance energy transfer (FRET) pair with l-(7-hydroxycoumarin-4-yl)ethylglycine (HCO, D) at position 17. Further, 6-CNTrp (A) was incorporated into two DNA binding proteins, including the Klenow fragment of DNA polymerase I and an RNA recognition motif (RRM2) of heterogeneous nuclear ribonucleoprotein L-like (hnRNP LL). Using these proteins, we demonstrated the use of FRET involving A as a fluorescence donor and benzo[g]quinazoline-2,4-(1H,3H)-dione 2′-deoxyriboside (Tf) or 4-aminobenzo[g]quinazoline-2-one 2′-deoxyriboside (Cf) as fluorescent acceptors to study the binding interaction of the Klenow fragment with duplex DNA oligomers (labeled with Tf), or the domain-specific association between hnRNP LL and the BCL2 i-motif DNA (labeled with Cf). Thus, the non-natural amino acid could be used as a FRET partner for studying protein-nucleic acid interactions. Together, these findings demonstrate the potential utility of 6-CNTrp (A) as a fluorescence donor for the study of protein conformational events.
AB - Described herein are the syntheses and photophysical characterization of three novel cyanotryptophans, and their efficient incorporation into proteins as fluorescent probes. Photophysical characteristics indicated that each was significantly brighter and red-shifted in fluorescence emission relative to tryptophan. Each analogue was used to activate a suppressor tRNA transcript and was incorporated with good efficiency into two different positions (Trp22 and Trp74) of Escherichia coli dihydrofolate reductase (ecDHFR). The Trp analogues could be monitored selectively in the presence of multiple native Trp residues in DHFR. 6-CNTrp (A) formed an efficient Förster resonance energy transfer (FRET) pair with l-(7-hydroxycoumarin-4-yl)ethylglycine (HCO, D) at position 17. Further, 6-CNTrp (A) was incorporated into two DNA binding proteins, including the Klenow fragment of DNA polymerase I and an RNA recognition motif (RRM2) of heterogeneous nuclear ribonucleoprotein L-like (hnRNP LL). Using these proteins, we demonstrated the use of FRET involving A as a fluorescence donor and benzo[g]quinazoline-2,4-(1H,3H)-dione 2′-deoxyriboside (Tf) or 4-aminobenzo[g]quinazoline-2-one 2′-deoxyriboside (Cf) as fluorescent acceptors to study the binding interaction of the Klenow fragment with duplex DNA oligomers (labeled with Tf), or the domain-specific association between hnRNP LL and the BCL2 i-motif DNA (labeled with Cf). Thus, the non-natural amino acid could be used as a FRET partner for studying protein-nucleic acid interactions. Together, these findings demonstrate the potential utility of 6-CNTrp (A) as a fluorescence donor for the study of protein conformational events.
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U2 - 10.1021/acs.biochem.5b01085
DO - 10.1021/acs.biochem.5b01085
M3 - Article
C2 - 26618501
AN - SCOPUS:84952836976
SN - 0006-2960
VL - 54
SP - 7457
EP - 7469
JO - Biochemistry
JF - Biochemistry
IS - 51
ER -