@article {2695,
	title = {Modulating the Mechanical Stability of Extracellular Matrix Protein Tenascin-C in a Controlled and Reversible Fashion},
	journal = {Journal of Molecular Biology},
	volume = {390},
	number = {4},
	year = {2009},
	note = {ISI Document Delivery No.: 477KYTimes Cited: 2Cited Reference Count: 45Zhuang, Shulin Peng, Qing Cao, Yi Li, Hongbin},
	month = {Jul},
	pages = {820-829},
	type = {Article},
	abstract = {Stretching force can induce conformational changes of proteins and is believed to be an important biological signal in the mechanotransduction network. Tenascin-C is a large extracellular matrix protein and is subject to stretching force under its physiological condition. Regulating the mechanical properties of the fibronectin type III domains of tenascin-C will alter its response to mechanical stretching force and thus may provide the possibility of regulating the biological activities of tenascin-C in living cells. However, tuning the mechanical stability of proteins in a rational and systematic fashion remains challenging. Using the third fibronectin type III domain (TNfn3) of tenascin-C as a model system, here we report a successful engineering of a mechanically stronger extracellular matrix protein via engineered metal chelation. Combining steered molecular dynamics simulations, protein engineering and single-molecule atomic force microscopy, we have rationally engineered a bihistidine-based metal chelation site into TNfn3. We used its metal chelation capability to selectively increase the unfolding energy barrier for the rate-limiting step during the mechanical unfolding of TNfn3. The resultant TNfn3 mutant exhibits enhanced mechanical stability. Using a stronger metal chelator, one can convert TNfn3 back to a state of lower mechanical stability. This is the first step toward engineering extracellular matrix proteins with defined mechanical properties, which can be modulated reversibly by external stimuli, and will provide the possibility of using external stimuli to regulate the biological functions of extracellular matrix proteins. (C) 2009 Elsevier Ltd. All rights reserved.},
	keywords = {DYNAMICS, ELASTICITY, ENGINEERING PROTEINS, FNIII DOMAIN, FRAGMENTS, MECHANICAL STABILITY, mechanical unfolding, microscopy, MOLECULE FORCE SPECTROSCOPY, MUSCLE, rational design, recombination, SINGLE PROTEIN, single-molecule force spectroscopy, tenascin},
	isbn = {0022-2836},
	url = {<Go to ISI>://000268519200019},
	author = {Zhuang, S. L. and Peng, Q. and Cao, Y. and Li, H. B.}
}
@article {2017,
	title = {Recombination of protein fragments: A promising approach toward engineering proteins with novel nanomechanical properties},
	journal = {Protein Science},
	volume = {17},
	number = {10},
	year = {2008},
	note = {ISI Document Delivery No.: 351CKTimes Cited: 4Cited Reference Count: 50Balamurali, M. M. Sharma, Deepak Chang, Anderson Khor, Dingyue Chu, Ricky Li, Hongbin},
	month = {Oct},
	pages = {1815-1826},
	type = {Article},
	abstract = {Combining single molecule atomic force microscopy (AFM) and protein engineering techniques, here we demonstrate that we can use recombination-based techniques to engineer novel elastomeric proteins by recombining protein fragments from structurally homologous parent proteins. Using I27 and I32 domains from the muscle protein titin as parent template proteins, we systematically shuffled the secondary structural elements of the two parent proteins and engineered 13 hybrid daughter proteins. Although I27 and I32 are highly homologous, and homology modeling predicted that the hybrid daughter proteins fold into structures that are similar to that of parent protein, we found that only eight of the 13 daughter proteins showed beta-sheet dominated structures that are similar to parent proteins, and the other five recombined proteins showed signatures of the formation of significant alpha-helical or random coil-like structure. Single molecule AFM revealed that six recombined daughter proteins are mechanically stable and exhibit mechanical properties that are different from the parent proteins. In contrast, another four of the hybrid proteins were found to be mechanically labile and unfold at forces that are lower than the similar to 20 pN, as we could not detect any unfolding force peaks. The last three hybrid proteins showed interesting duality in their mechanical unfolding behaviors. These results demonstrate the great potential of using recombination-based approaches to engineer novel elastomeric protein domains of diverse mechanical properties. Moreover, our results also revealed the challenges and complexity of developing a recombination-based approach into a laboratory-based directed evolution approach to engineer novel elastomeric proteins.},
	keywords = {ATOMIC-FORCE MICROSCOPY, BIOLOGICAL ROLES, COMPUTATIONAL DESIGN, ELASTICITY, elastomeric protein, EVOLUTION, IMMUNOGLOBULIN DOMAINS, MECHANICAL STABILITY, mechanical unfolding, MOLECULAR-DYNAMICS SIMULATION, recombination, SEQUENCE, SINGLE PROTEIN, single-molecule force spectroscopy, TITIN},
	isbn = {0961-8368},
	url = {<Go to ISI>://000259401900019},
	author = {Balamurali, M. M. and Sharma, D. and Chang, A. and Khor, D. and Chu, R. 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 {1555,
	title = {Engineering proteins with novel mechanical properties by recombination of protein fragments},
	journal = {Angewandte Chemie-International Edition},
	volume = {45},
	number = {34},
	year = {2006},
	note = {ISI Document Delivery No.: 082MRTimes Cited: 20Cited Reference Count: 51Sharma, Deepak Cao, Yi Li, Hongbin},
	pages = {5633-5638},
	type = {Article},
	keywords = {AFM, ATOMIC-FORCE MICROSCOPY, ELASTICITY, EVOLUTION, IG DOMAIN, IMMUNOGLOBULIN DOMAINS, MOLECULAR-DYNAMICS SIMULATIONS, protein engineering, protein structures, scanning probe microscopy, SINGLE PROTEIN, single-molecule studies, SPECTROSCOPY, STABILITY, TITIN},
	isbn = {1433-7851},
	url = {<Go to ISI>://000240391400016},
	author = {Sharma, D. and Cao, Y. and Li, H. B.}
}
@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.}
}
