채필석
2017-07-28T06:25:08Z
2017-07-28T06:25:08Z
2015-10
BIOCHEMISTRY, v. 54, NO 38, Page. 5849-5855
0006-2960
http://pubs.acs.org/doi/10.1021/acs.biochem.5b00660
http://hdl.handle.net/20.500.11754/28097
The effect of various detergents on the stability and function of the melibiose permeases of Escherichia coli (MelB(Ec)) and Salmonella typhimurium (MelB(st)) was studied. In n-dodecyl-beta-D-maltoside (DDM) or n-undecyl-beta-Dmaltoside (UDM), WT MelBst binds melibiose with an affinity similar to that in the membrane. However, with WT MelB(Ec), or MelB(st) mutants (Arg141 -˃ Cys, Arg295 -˃ Cys, or Arg363 -˃ Cys), galactoside binding is not detected in these detergents, but binding to the phosphotransferase protein IIA(Glc) is maintained. In the amphiphiles lauryl maltose neopentyl glycol (MNG-3) or glyco-diosgenin (GDN), galactoside binding with all of the MelB proteins is observed, with slightly reduced affinities. MelB(st) is more therrnostable than MelB(Ec) and the thermostability of either MelB is largely increased in MNG-3 or GDN. Therefore, the functional defect with DDM or UDM likely results from the relative instability of the sensitive MelB proteins, and stability, as well as galactoside binding, is retained in MNG-3 or GDN. Furthermore, isothermal titration calorirnetry of melibiose binding with MelB(st) shows that the favorable entropic contribution to the binding free energy is decreased in MNG-3, indicating that the conformational dynamics of MelB is restricted in this detergent.
This work was supported in part by the National Science Foundation, Directorate for Biological Sciences (grant MCB-1158085 to L.G.); by the U.S. Department of Health and Human Services, National Institutes of Health (grant R01 GM095538 to L.G.); and by the Korean government (MSIP), the National Research Foundation of Korea (grant 2013R1A2A2A03067623 to P.S.C.).
en
AMER CHEMICAL SOC
RESONANCE ENERGY-TRANSFER
SEROVAR TYPHIMURIUM MELB
ESCHERICHIA-COLI
LACTOSE PERMEASE
TRANSPORT PROTEINS
MEMBRANE-VESICLES
NA+
STABILIZATION
AMPHIPHILES
MECHANISM
Effect of Detergents on Galactoside Binding by Melibiose Permeases
Article
38
54
10.1021/acs.biochem.5b00660
5849-5855
BIOCHEMISTRY
Amin, Anowarul
Hariharan, Parameswaran
Chae, Pil Seok
Guan, Lan
2015000442
S
GRADUATE SCHOOL[S]
DEPARTMENT OF BIONANOTECHNOLOGY
pchae