1. We have simultaneously collected composition-dependent static and dynamic light scattering data on mixtures of non-interacting and interacting proteins, and developed a global analysis of the composition-dependence of both quantities. Contrary to expectation, addition of dynamic light scattering data did not enhance the resolution of characterization obtainable using static light scattering data only. A preliminary description of this work was presented in last year's report, but analysis of the data has since been refined and extended, enabling a more detailed analysis of the relative information content of the two types of data. (B. Monterroso, CIB) 2. We have measured the dependence of the intensity of light scattering upon protein concentration in solutions of FtsZ containing either GTP an a GTP-regenerating system or GPCPP, a slowly hydrolyzable GTP analog, in the presence of varying concentrations of Mg++ ion. The simplest interpretation of the observed dependence is that self-association of either FtsZ-GTP or FtsZ-GPCPP proceeds initially by linear growtn according to an indefinite isodesmic scheme, followed by cooperative formation of a stable oligomer or narrow size distribution of oligomers of size 30-40 subunits that are thought to be cyclic. A preliminary description of this work was presented in last year's report. During the last year, the static light scattering results have been extended to include angular dependence, and results obtained from measurements of dynamic light scattering and sedimentation have enabled a significant refinement and extension of conclusions previously derived (G. Rivas, CIB).

Project Start
Project End
Budget Start
Budget End
Support Year
5
Fiscal Year
2011
Total Cost
$307,736
Indirect Cost
City
State
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Wu, Di; Minton, Allen P (2015) Quantitative characterization of nonspecific self- and hetero-interactions of proteins in nonideal solutions via static light scattering. J Phys Chem B 119:1891-8
Wu, Di; Minton, Allen P (2013) Compensating effects of urea and trimethylamine-N-oxide on the heteroassociation of ?-chymotrypsin and soybean trypsin inhibitor. J Phys Chem B 117:3554-9
Wu, Di; Minton, Allen P (2013) Quantitative characterization of the compensating effects of trimethylamine-N-oxide and guanidine hydrochloride on the dissociation of human cyanmethmoglobin. J Phys Chem B 117:9395-9
Wu, Di; Minton, Allen P (2013) Quantitative characterization of the interaction between sucrose and native proteins via static light scattering. J Phys Chem B 117:111-7
Monterroso, Begoña; Ahijado-Guzmán, Rubén; Reija, Belén et al. (2012) Mg(2+)-linked self-assembly of FtsZ in the presence of GTP or a GTP analogue involves the concerted formation of a narrow size distribution of oligomeric species. Biochemistry 51:4541-50
Monterroso, Begoña; Rivas, Germán; Minton, Allen P (2012) An equilibrium model for the Mg(2+)-linked self-assembly of FtsZ in the presence of GTP or a GTP analogue. Biochemistry 51:6108-13
Fernández, Cristina; Minton, Allen P (2011) Effect of nonadditive repulsive intermolecular interactions on the light scattering of concentrated protein-osmolyte mixtures. J Phys Chem B 115:1289-93
Rivas, Germán; Minton, Allen P (2011) Beyond the second virial coefficient: Sedimentation equilibrium in highly non-ideal solutions. Methods 54:167-74
Attri, Arun K; Fernández, Cristina; Minton, Allen P (2010) pH-dependent self-association of zinc-free insulin characterized by concentration-gradient static light scattering. Biophys Chem 148:28-33
Attri, Arun K; Fernández, Cristina; Minton, Allen P (2010) Self-association of Zn-insulin at neutral pH: investigation by concentration gradient--static and dynamic light scattering. Biophys Chem 148:23-7

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