Conformational analysis of a IgG1 hinge peptide derivative in solution determined by NMR spectroscopy and refined by restrained molecular dynamics simulations
1991; Wiley; Volume: 31; Issue: 10 Linguagem: Inglês
10.1002/bip.360311007
ISSN1097-0282
AutoresHorst Kessler, Siggi Mronga, Gerhard Müller, Luis Moroder, R. Huber,
Tópico(s)Protein Structure and Dynamics
ResumoAbstract The hinge region links the antigen binding F ab part to the constant F c domain in immunoglobulins. For the hinge peptide derivative [AcThr(OtBu)‐Cys‐Pro‐Pro‐Cys‐Pro‐Ala‐ProNH 2 ] 2 the assignment of the 1 H and 13 C resonances was achieved by two‐dimensional nmr techniques: total correlation spectroscopy (TOCSY), nuclear Ovethauser enhancement spectroscopy (NOESY), rotating frame nuclear Overhauser enhancement spectroscopy (ROESY), heteronuclear multiple quantum coherence (HMQC) transfer, and a HSQC (modified Overbodenhausen experiment) with high resolution in F 1 , which was several times folded in F 1 but still phase correctable. Conformational relevant parameters (78 nuclear Overhauser effect distance restraints, 3 J HH for prochiral assignments, temperature gradients) were determined by nmr and served as input data for molecular dynamics (MD) structure refinement. A simulated model compound corresponding to the [Cys‐Pro‐Pro‐Cys] 2 core elongated by the peptide chains in the F ab and F c direction served as a starting structure for the final MD run. The conformation calculated in in vacuo does not agree with the C 2 symmetry required from nmr data, but the structure obtained by a water simulation fulfills the requirement. Here the core of the hinge peptide derivative adopts a polyproline II double helix as in the x‐ray structure of IgG1. Hence, segments responsible for the internal flexibility are located outside the core as confirmed by the flexibility of the solvent exposed C termini.
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