TY - JOUR
T1 - Structure, topology and assembly of a 32-mer peptide corresponding to the loop 3 and transmembrane domain 4 of divalent metal transporter (DMT1) in membrane-mimetic environments
AU - Li, Hongyan
AU - Gu, Ji Dong
AU - Sun, Hongzhe
N1 - Funding Information:
We thank the University of Hong Kong, Hong Kong Research Grants Council for a Central Allocation (HKU2/06 and HKUST3/04C) and the Area of Excellence Scheme of the University Grants Committee (Hong Kong) for financial support as well as an equipment grant from the University of Hong Kong (UDF) for purchase of the 600-MHz NMR spectrometer.
PY - 2008/5
Y1 - 2008/5
N2 - Divalent metal transporter (DMT1) belongs to the family of Nramp proteins. The fourth transmembrane domain (TM4) housing the disease-causing mutations both in Nramp1 and Nramp2 at the conserved two adjacent glycine residues, was implicated to serve an important biological function. In the present study, we have characterized structurally and topologically a 32-mer synthetic peptide, corresponding to the sequence of the loop 3 and the fourth transmembrane domain of rat DMT1 in membrane-mimetic environments (e.g. TFE, SDS micelles) using both CD and NMR spectroscopic techniques. Solution structures derived from NMR and molecular dynamic/simulated annealing calculation demonstrated that the peptide exhibits a highly defined α-helice in the middle portion of the peptide, flanked by a highly flexible N-terminus and a relatively ordered C-terminus. Paramagnetic broadening on peptide signals by spin-labels and Mn2+ suggested that both the N-terminus and helical core of the peptide were embedded into the SDS micelles. The peptide exhibited amphipathic characteristics, with hydrophilic residues (Thr189, Asp192, Thr193 and Asp200) lying in one side of the helix which provides a basis for the formation of water-filled channel architectures through self-associations. Diffusion-ordered spectroscopy (DOSY) indicated that the peptide exhibits mixtures of hexamers, trimers and monomers, in contrast to the fourth transmembrane peptide (24-mer) being aggregated as a trimer only. This appears to be the first report on the effects of loops on aggregation behavior of transmembrane domains in membrane-mimetic environments.
AB - Divalent metal transporter (DMT1) belongs to the family of Nramp proteins. The fourth transmembrane domain (TM4) housing the disease-causing mutations both in Nramp1 and Nramp2 at the conserved two adjacent glycine residues, was implicated to serve an important biological function. In the present study, we have characterized structurally and topologically a 32-mer synthetic peptide, corresponding to the sequence of the loop 3 and the fourth transmembrane domain of rat DMT1 in membrane-mimetic environments (e.g. TFE, SDS micelles) using both CD and NMR spectroscopic techniques. Solution structures derived from NMR and molecular dynamic/simulated annealing calculation demonstrated that the peptide exhibits a highly defined α-helice in the middle portion of the peptide, flanked by a highly flexible N-terminus and a relatively ordered C-terminus. Paramagnetic broadening on peptide signals by spin-labels and Mn2+ suggested that both the N-terminus and helical core of the peptide were embedded into the SDS micelles. The peptide exhibited amphipathic characteristics, with hydrophilic residues (Thr189, Asp192, Thr193 and Asp200) lying in one side of the helix which provides a basis for the formation of water-filled channel architectures through self-associations. Diffusion-ordered spectroscopy (DOSY) indicated that the peptide exhibits mixtures of hexamers, trimers and monomers, in contrast to the fourth transmembrane peptide (24-mer) being aggregated as a trimer only. This appears to be the first report on the effects of loops on aggregation behavior of transmembrane domains in membrane-mimetic environments.
KW - Divalent metal transporter (DMT1)
KW - NMR structure
KW - SDS micelles
KW - Transmembrane peptide
UR - http://www.scopus.com/inward/record.url?scp=41949121798&partnerID=8YFLogxK
U2 - 10.1016/j.jinorgbio.2007.12.019
DO - 10.1016/j.jinorgbio.2007.12.019
M3 - 文章
C2 - 18243325
AN - SCOPUS:41949121798
SN - 0162-0134
VL - 102
SP - 1257
EP - 1266
JO - Journal of Inorganic Biochemistry
JF - Journal of Inorganic Biochemistry
IS - 5-6
ER -