TY - JOUR
T1 - Solution Structure of the D/E Helix Linker of Skeletal Troponin-C
T2 - As Studied by Circular Dichroism and Two-Dimensional NMR Spectroscopy
AU - Lee, Weontae
AU - Krishna, N. Rama
AU - Anatharamaiah, G. M.
AU - Cheung, Herbert C.
PY - 1998/1/20
Y1 - 1998/1/20
N2 - We have synthesized a 17-residue peptide with the amino acid sequence RQMKEDAKGKSEEELAD corresponding to residues 84-100 of chicken skeletal troponin C. This stretch of the protein sequence is in the middle one-third of the 32-residue 9-turn α-helix that connects the two globular domains of the dumbell-shaped molecule and includes the D/E linker helix. We describe here the solution conformation of the helix linker as studied by circular dichroism (CD) and two-dimensional nuclear magnetic resonance (2-D NMR) spectroscopy. The NOE connectivities together with the vicinal 3JNα coupling constants suggest that the peptide exists in a fast conformational equilibrium among several secondary structures: a nascent helix near the N-terminus, a helix, and a substational population of extended and random coil forms. In addition, two interresidue α-α NOEs are observed suggesting a bent structure with a bend that includes the single glycine in position 92. These results are consistent with the ideas that in neutral solution the D/E linker region of the central helix in troponin C can adopt a helical conformation and the central helix may have a segmental flexibility around Gly 92.
AB - We have synthesized a 17-residue peptide with the amino acid sequence RQMKEDAKGKSEEELAD corresponding to residues 84-100 of chicken skeletal troponin C. This stretch of the protein sequence is in the middle one-third of the 32-residue 9-turn α-helix that connects the two globular domains of the dumbell-shaped molecule and includes the D/E linker helix. We describe here the solution conformation of the helix linker as studied by circular dichroism (CD) and two-dimensional nuclear magnetic resonance (2-D NMR) spectroscopy. The NOE connectivities together with the vicinal 3JNα coupling constants suggest that the peptide exists in a fast conformational equilibrium among several secondary structures: a nascent helix near the N-terminus, a helix, and a substational population of extended and random coil forms. In addition, two interresidue α-α NOEs are observed suggesting a bent structure with a bend that includes the single glycine in position 92. These results are consistent with the ideas that in neutral solution the D/E linker region of the central helix in troponin C can adopt a helical conformation and the central helix may have a segmental flexibility around Gly 92.
UR - http://www.scopus.com/inward/record.url?scp=0542372754&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0542372754&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:0542372754
VL - 19
SP - 57
EP - 62
JO - Bulletin of the Korean Chemical Society
JF - Bulletin of the Korean Chemical Society
SN - 0253-2964
IS - 1
ER -