Tamura Masato, Sekiguchi Tsubasa, Ishiuchi Shun-Ichi, Zehnacker-Rentien Anne, Fujii Masaaki
Laboratory for Chemistry and Life Science, Institute of Innovative Research , Tokyo Institute of Technology , 4259 Nagatsuta-cho, Midori-ku , Yokohama , 226-8503 , Japan.
School of Life Science and Technology , Tokyo Institute of Technology , 4259 Nagatsuta-cho, Midori-ku , Yokohama , Kanagawa 226-8501 , Japan.
J Phys Chem Lett. 2019 May 16;10(10):2470-2474. doi: 10.1021/acs.jpclett.9b00184. Epub 2019 May 2.
Chirality plays an essential role in biological molecular recognition, such as neurotransmission. Here, we applied electrospray-cold ion trap spectroscopy to complexes of a partial binding motif SIVSF of a β-adrenergic receptor pocket with L- and D-epinephrine AdH. The ultraviolet spectrum of the SIVSF-AdH complex changed drastically when L-AdH was replaced by its enantiomer. The isomer-selected infrared spectra revealed that D-AdH was bound to SIVSF by its protonated amino-group or a single catechol OH and induced nonhelical secondary structures of SIVSF. This is in sharp contrast to the helical SIVSF complex with L-AdH, which is close to the natural binding structure with two catechol OHs binding in the receptor. This shows that a short pentapeptide SIVSF can distinguish the chirality of the ligand AdH as well as the receptor. This stereoselectivity is suggested to arise from an additional interaction involving the hydroxyl group on the chiral carbon.
手性在生物分子识别中起着至关重要的作用，如神经传递。在此，我们将电喷雾冷离子阱光谱应用于β-肾上腺素能受体口袋的部分结合基序SIVSF与L-和D-肾上腺素（AdH）的复合物。当L-AdH被其对映体取代时，SIVSF-AdH复合物的紫外光谱发生了急剧变化。异构体选择红外光谱表明，D-AdH通过其质子化氨基或单个儿茶酚羟基与SIVSF结合，并诱导了SIVSF的非螺旋二级结构。这与SIVSF与L-AdH形成的螺旋复合物形成了鲜明对比，后者接近受体中两个儿茶酚羟基结合的天然结合结构。这表明短五肽SIVSF能够区分配体AdH以及受体的手性。这种立体选择性被认为源于涉及手性碳上羟基的额外相互作用。
