Study on molecular interactions between proteins on live cell membranes using quantum dot-based fluorescence resonance energy transfer.
Mouse anti-human CD71 monoclonal antibody (anti-CD71) was conjugated with red quantum dots (QDs; 5.3 nm, emission wavelength lambda(em) = 614 nm) and used to label HeLa cells successfully. Then green QD-labeled goat anti-mouse immunoglobulin G (IgG; the size of the green QDs was 2.2 nm; lambda(em) = 544 nm) was added to bind the red-QD-conjugated anti-CD71 on the cell surface by immunoreactions. Such interaction between anti-CD71 and IgG lasted 4 min and was observed from the fluorescence spectra: the fluorescence intensity of the "red" peak at 614 nm increased by 32%; meanwhile that of the "green" one at 544 nm decreased by 55%. The ratio of the fluorescence intensities (I(544 nm)/I(614 nm)) decreased from 0.5 to 0.2. The fluorescence spectra as well as cell imaging showed that fluorescence resonance energy transfer took place between these two kinds of QDs on the HeLa cells through interactions between the primary antibody and the secondary antibody.
Liu
Tian-Cai
TC
Key Laboratory of Biomedical Photonics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, HuBei, 430074, China.
Zhang
Hai-Li
HL
Wang
Jian-Hao
JH
Wang
Hai-Qiao
HQ
Zhang
Zhi-Hong
ZH
Hua
Xiao-Feng
XF
Cao
Yuan-Cheng
YC
Luo
Qing-Ming
QM
Zhao
Yuan-Di
YD
D000911:Antibodies, Monoclonal / Q000737:chemistry; D015703:Antigens, CD / Q000737:chemistry / Q000378:metabolism; D002462:Cell Membrane / Q000737:chemistry* / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D006367:HeLa Cells; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D015335:Molecular Probes / Q000737:chemistry*; D045663:Quantum Dots; D011990:Receptors, Transferrin / Q000737:chemistry / Q000378:metabolism
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; C068126:CD71 antigen; D007074:Immunoglobulin G; D008565:Membrane Proteins; D015335:Molecular Probes; D011990:Receptors, Transferrin