@article {2149,
	title = {Configurational entropy modulates the mechanical stability of protein GB1},
	journal = {Journal of Molecular Biology},
	volume = {379},
	number = {4},
	year = {2008},
	note = {ISI Document Delivery No.: 314NITimes Cited: 10Cited Reference Count: 39Li, Hongbin Wang, Hui-Chuan Cao, Yi Sharma, Deepak Wang, Meijia},
	month = {Jun},
	pages = {871-880},
	type = {Article},
	abstract = {Configurational entropy plays important roles in defining the thermodynamic stability as well as the folding/unfolding kinetics of proteins. Here we combine single-molecule atomic force microscopy and protein engineering techniques to directly examine the role of configurational entropy in the mechanical unfolding kinetics and mechanical stability of proteins. We used a small protein, GB1, as a model system and constructed four mutants that elongate loop 2 of GB1 by 2, 5, 24 and 46 flexible residues, respectively. These loop elongation mutants fold properly as determined by far-UV circular dichroism spectroscopy, suggesting that loop 2 is well tolerant of loop insertions without affecting GB1{\textquoteright}s native structure. Our single-molecule atomic force microscopy results reveal that loop elongation decreases the mechanical stability of GB1 and accelerates the mechanical unfolding kinetics. These results can be explained by the loss of configurational entropy upon closing an unstructured flexible loop using classical polymer theory, highlighting the important role of loop regions in the mechanical unfolding of proteins. This study not only demonstrates a general approach to investigating the structural deformation of the loop regions in mechanical unfolding transition state, but also provides the foundation to use configurational entropy as an effective means to modulate the mechanical stability of proteins, which is of critical importance towards engineering artificial elastomeric proteins with tailored nanomechanical properties. (C) 2008 Elsevier Ltd. All rights reserved.},
	keywords = {configurational entropy, DISULFIDE BONDS, FORCE, FORCE SPECTROSCOPY, FRAGMENT RECONSTITUTION, IMMUNOGLOBULIN BINDING DOMAIN, length, LOOP, MECHANICAL STABILITY, mechanical unfolding, MODULES, resistance, single molecule atomic force microscopy, SINGLE PROTEIN, SPECTROSCOPY, TITIN, TRANSITION-STATE},
	isbn = {0022-2836},
	url = {<Go to ISI>://000256815700018},
	author = {Li, H. B. and Wang, H. C. and Cao, Y. and Sharma, D. and Wang, M.}
}
@article {1349,
	title = {Nonmechanical protein can have significant mechanical stability},
	journal = {Angewandte Chemie-International Edition},
	volume = {45},
	number = {4},
	year = {2006},
	note = {ISI Document Delivery No.: 004RFTimes Cited: 30Cited Reference Count: 44},
	pages = {642-645},
	type = {Article},
	keywords = {ADHESION, cell, DISULFIDE BONDS, DYNAMICS, ELASTICITY, mechanical properties, microscopy, MOLECULE FORCE-SPECTROSCOPY, protein unfolding, resistance, scanning probe microscopy, SIMULATION, SINGLE PROTEIN, single-molecule studies, TITIN IMMUNOGLOBULIN DOMAINS},
	isbn = {1433-7851},
	url = {<Go to ISI>://000234769200026},
	author = {Cao, Y. and Lam, C. and Wang, M. J. and Li, H. B.}
}
@article {7352,
	title = {STABILIZATION OF THE STRUCTURE OF HORSE PLASMA VITAMIN-D BINDING-PROTEIN BY DISULFIDE BONDS},
	journal = {Biochemistry and Cell Biology-Biochimie Et Biologie Cellulaire},
	volume = {70},
	number = {1},
	year = {1992},
	note = {ISI Document Delivery No.: HG742Times Cited: 1Cited Reference Count: 27},
	month = {Jan},
	pages = {10-15},
	type = {Article},
	abstract = {Vitamin D binding protein (DBP) was isolated from horse plasma in a four-step procedure that involved Affi-Gel Blue affinity chromatography, gel filtration, hydroxylapatite chromatography, and anion exchange high-pressure liquid chromatography. The yield of DBP from 80 mL of plasma was 6-7 mg. Horse plasma DBP closely resembles other plasma DBPs, being a tryptophan-free protein of M(r) 53 000. It is able to bind to and block the polymerization of monomeric actin. The secondary structure of DBP was calculated from circular dichroism measurements to be 39\% alpha-helix, 42\% beta-sheet, and 19\% random coil. Circular dichroism and fluorescence studies revealed that the disulfide bonds of DBP contribute substantial structural stabilization to the molecule with respect to thermal denaturation. The thermal stability of DBP can be used to advantage. Incorporation of a brief treatment at 70-degrees-C into the preparative scheme enables omission of one chromatographic step, without detectable alteration of the purified product.},
	keywords = {actin, circular dichroism, CIRCULAR-DICHROISM, COMPLEX, denaturation, DISULFIDE BONDS, FLUORESCENCE, GC-GLOBULIN, POLYMERIZATION, RAT, SERUM, thermal, TROPOMYOSIN, VITAMIN-D BINDING PROTEIN},
	isbn = {0829-8211},
	url = {<Go to ISI>://A1992HG74200002},
	author = {Robinson, R. C. and Burtnick, L. D.}
}
