Complement assembly of two fragments of the streptococcal protein G B1 domain in aqueous solution

[摘要]

We examined the complementation of various pairs of fragments derived from the streptococcal protein G B1 domain by NMR and CD. Most were not associated; however, one pair of fragments (1–40) and (41–56) interacted sufficiently enoughto regenerate a stable 1:1 complex, K _d = 9 × 10⁻⁶M. A 2D-NMR analysis showed that the structure of the complex resembled that of native domain. Here we discuss the complementation from the viewpoint of the folding pathway of the protein.

[学科分类] 生物化学/生物物理

[关键词] Protein G;Protein folding;Complementation;Nuclear magnetic resonance;Circular dichroism;CD;circular dichroism;d aN(ij);intramolecular distance between the protons CαH and NH on the residues i and j;DQF-COSY;two-dimensional double quantum-filtered coherence transfer spectroscopy;HOHAHA;two-dimensional homo-nuclear Hartmann-Hahn spectroscopy;K d;dissociation constant;NOESY;two-dimensional nuclear Overhauser and exchange spectroscopy;PGB1;protein G B1 domain;ROESY;two-dimensional rotating frame nuclear Overhauser and exchange spectroscopy;[x + y];equimolar mixture of fragments x and y;NMR;nuclear magnetic resonance