速報感想 by ZHU 2013/4/8
本間さん、Nature 7440, 7441, 7442
1, Taruno, A., et al. CALHM1 ion channel mediates purinergic neurotransmission of sweet, bitter and umami tastes. Nature 495:223-226.
A discovery of the type II receptor cell relating to tastes is helpful for the researcher who firstly proposed to deserve Nobel Prize. One kind of ion channel named as CALHM1 is located in the type II receptor cell. This paper mentioned that this ion channel is involved in progress of neurotransmission of sweet, bitter and umami tastes and give us a model about a role of this ion channel during the transmitting of signal. A conformational change of this channel will regulate the concentration of ATP and result in cascaded reaction of presynaptic cell.
2, Toyoshima, C., et al. Crystal structures of the calcium pump and sarcolipin in the Mg2+-bound E1 state. Nature 495: 260-264.
Calcium pump has been resolved years ago. However, the mechanism of this pump's working is still obscure. This paper revealed a crystal structure of calcium pump in the E1 state with a Mg2+ ion. Combined to E1 structure with Calcium ions, they suggested that a Mg2+ firstly attached to a binding site of Calcium at this pump due to a higher affinity of Mg2+ than that of Ca2+. Then, the structure will be changed to another state to be easier to accept to 2 Ca2+ ions at the binding site. This result allows us to understand this working mechanism in details. This is crystal period!
米田さん130408 PNAS Vol. 109 no. 38
Dynamics of the L-fucose/H+ symporter revealed by fluorescence spectroscopy. Junichi Sugihara, et al.
FucP, as one kind of major facilitator superfamily (MFS) transporters has been published on the Nature journal. This time, authors analyzed its structure change by the fluorescence spectroscopy. They found that W38 and W278 are involved in the conformational dynamic. Especially, a mutation at W38 decreased affinity of FucP to fucose. Finally, they proposed that sugar binding these two residues caused FucP to form an occluded intermediated state.