@article {2035,
	title = {Protein-protein interaction regulates proteins{\textquoteright} mechanical stability},
	journal = {Journal of Molecular Biology},
	volume = {378},
	number = {5},
	year = {2008},
	note = {ISI Document Delivery No.: 305IOTimes Cited: 10Cited Reference Count: 38Cao, Yi Yoo, Teri Zhuang, Shulin Li, Hongbin},
	month = {May},
	pages = {1132-1141},
	type = {Article},
	abstract = {Elastomeric proteins are molecular springs found not only in a variety of biological machines and tissues, but also in biomaterials of superb mechanical properties. Regulating the mechanical stability of elastomeric proteins is not only important for a range of biological processes, but also critical for the use of engineered elastomeric proteins as building blocks to construct nanomechanical devices and novel materials of well-defined mechanical properties. Here we demonstrate that protein-protein interactions can potentially serve as an effective means to regulate the mechanical properties of elastomeric proteins. We show that the binding of fragments of IgG antibody to a small protein, GB1, can significantly enhance the mechanical stability of GB1. The regulation of the mechanical stability of GB1 by IgG fragments is not through direct modification of the interactions in the mechanically key region of GB1; instead, it is accomplished via the long-range coupling between the IgG binding site and the mechanically key region of GB1. Although Fc and Fab bind GB1 at different regions of GB1, their binding to GB1 can increase the mechanical stability of GB1 significantly. Using alanine point mutants of GB1, we show that the amplitude of mechanical stability enhancement of GB1 by Fc does not correlate with the binding affinity, suggesting that binding affinity only affects the population of GB1/human Fc (hFc) complex at a given concentration of hFc, but does not affect the intrinsic mechanical stability of the GB1/hFc complex. Furthermore, our results indicate that the mechanical stability enhancement by IgG fragments is robust and can tolerate sequence/structural perturbation to GB1. Our results demonstrate that the protein-protein interaction is an efficient approach to regulate the mechanical stability of GB1-like proteins and we anticipate that this new methodology will help to develop novel elastomeric proteins with tunable mechanical stability and compliance. (C) 2008 Elsevier Ltd. All rights reserved.},
	keywords = {BINDING, BIOLOGICAL ROLES, CRYSTAL-STRUCTURE, DIHYDROFOLATE-REDUCTASE, DOMAIN, ENGINEERING PROTEINS, FORCE SPECTROSCOPY, FRAGMENT, HUMAN-IGG, MECHANICAL STABILITY, mechanical unfolding, MOLECULAR ELASTICITY, protein-protein interaction, single molecule atomic force microscopy, STABILIZATION},
	isbn = {0022-2836},
	url = {<Go to ISI>://000256171900015},
	author = {Cao, Y. and Yoo, T. and Zhuang, S. L. and Li, H. B.}
}
@article {2034,
	title = {Single molecule force spectroscopy reveals engineered metal chelation is a general approach to enhance mechanical stability of proteins},
	journal = {Proceedings of the National Academy of Sciences of the United States of America},
	volume = {105},
	number = {32},
	year = {2008},
	note = {ISI Document Delivery No.: 339EKTimes Cited: 16Cited Reference Count: 44Cao, Yi Yoo, Teri Li, Hongbin},
	month = {Aug},
	pages = {11152-11157},
	type = {Article},
	abstract = {Significant mechanical stability is an essential feature shared by many elastomeric proteins, which function as molecular springs in a wide variety of biological machinery and biomaterials of superb mechanical properties. Despite the progress in understanding molecular determinants of mechanical stability, it remains challenging to rationally enhance the mechanical stability of proteins. Using single molecule force spectroscopy and protein engineering techniques, we demonstrate that engineered bi-histidine metal chelation can enhance the mechanical stability of proteins significantly and reversibly. Based on simple thermodynamic cycle analysis, we engineered a bi-histidine metal chelation site into various locations of the small protein, GB1, to achieve preferential stabilization of the native state over the mechanical unfolding transition state of GB1 through the binding of metal ions. Our results demonstrate that the metal chelation can enhance the mechanical stability of GB1 by as much as 100 pN. Since bi-histidine metal chelation sites can be easily implemented, engineered metal chelation provides a general methodology to enhance the mechanical stability of a wide variety of proteins. This general approach in protein mechanics will enable the rational tuning of the mechanical stability of proteins. It will not only open new avenues toward engineering proteins of tailored nanomechanical properties, but also provide new approaches to systematically map the mechanical unfolding pathway of proteins.},
	keywords = {BINDING SITES, charge, DESIGN, DOMAINS, ELASTICITY, engineering, EXTRACELLULAR-MATRIX PROTEIN, mechanical unfolding, PROTEIN, protein mechanics, rational design, SIMULATIONS, STABILIZATION, STRENGTH, THERMOSTABILITY, TITIN},
	isbn = {0027-8424},
	url = {<Go to ISI>://000258560700024},
	author = {Cao, Y. and Yoo, T. and Li, H. B.}
}
@article {679,
	title = {Ketonization of incarcerated acetophenone enol},
	journal = {Journal of the American Chemical Society},
	volume = {125},
	number = {32},
	year = {2003},
	note = {ISI Document Delivery No.: 709YTTimes Cited: 18Cited Reference Count: 25},
	month = {Aug},
	pages = {9558-9559},
	type = {Article},
	keywords = {ALKYL KETONES, CONSEQUENCES, HEMICARCERAND, INNER PHASE, PHOTOCHEMICAL REACTIVITY, STABILIZATION},
	isbn = {0002-7863},
	url = {<Go to ISI>://000184654700009},
	author = {Makeiff, D. A. and Vishnumurthy, K. and Sherman, J. C.}
}
@article {4155,
	title = {Intermolecular interactions of lysozyme and small alcohols: A calorimetric investigation},
	journal = {Journal of Physical Chemistry B},
	volume = {101},
	number = {29},
	year = {1997},
	note = {ISI Document Delivery No.: XM058Times Cited: 23Cited Reference Count: 34},
	month = {Jul},
	pages = {5755-5758},
	type = {Article},
	abstract = {Isothermal titration calorimetry was used to measure transfer enthalpies of hen egg white lysozyme from water to aqueous solutions of methanol, ethanol, 1-propanol, glycerol, and 2,2,2-trifluoroethanol. Excess partial molar enthalpies of lysozyme at infinite dilution in the alcoholic solvents, H-infinity(L)E, were calculated, and the dependence of H-infinity(L)E on the concentration of the alcohol, was utilized to elucidate the enthalpy of alcohol-protein interactions. Results show that, at low alcohol concentrations, alcohol-protein interactions are unfavorable in terms of enthalpy (endothermic), while at higher concentrations they are favorable (exothermic). The change from endothermic to exothermic interactions happened sharply over a narrow alcohol concentration interval, and was found to occur concurrently with denaturation of the protein in some but not all cases. Comparison of the present results with previous investigations of simple binary and ternary aqueous solutions suggests that the change of sign of the interaction enthalpy is related to the water-water hydrogen bonding properties in the alcohol mixtures. It is argued that modifications by the alcohol of the percolated hydrogen bond network govern the enthalpy of alcohol-lysozyme interactions in the most water-rich samples. This suggests that occupancy by the alcohol of a binding site on the surface of the protein may not be necessary for the alcohol to affect the properties of the protein. At higher alcohol concentrations the observed interaction enthalpies are dominated by direct ({\textquoteright}{\textquoteright}intrinsic{\textquoteright}{\textquoteright}) effects of protein-alcohol interactions, which are exothermic.},
	keywords = {25-DEGREES-C, ENERGIES, GLOBULAR-PROTEINS, INDUCED REVERSIBLE DENATURATION, MIXTURES, MONOHYDRIC ALCOHOLS, STABILIZATION, THERMODYNAMIC INVESTIGATIONS, TRIFLUOROETHANOL, VAPOR-PRESSURES, WATER},
	isbn = {1089-5647},
	url = {<Go to ISI>://A1997XM05800021},
	author = {Westh, P. and Koga,Yoshikata}
}
