@article {2378,
	title = {NMR Spectroscopic Characterization of the Sialyltransferase CstII from Campylobacter jejuni: Histidine 188 Is the General Base},
	journal = {Biochemistry},
	volume = {48},
	number = {47},
	year = {2009},
	note = {ISI Document Delivery No.: 521UVTimes Cited: 2Cited Reference Count: 55Chan, Patrick H. W. Lairson, Luke L. Lee, Ho Jun Wakarchuk, Warren W. Strynadka, Natalie C. J. Withers, Stephen G. McIntosh, Lawrence P.},
	month = {Dec},
	pages = {11220-11230},
	type = {Article},
	abstract = {Cell surface glycans are often terminated by sialic acid, which is incorporated onto sugar acceptors by sialyltransferases. The crystal structure of the GT family 42 Campylobacter jejuni alpha-2,3/2,8-sialyltransferase (CstII) provides key insights into the sialyl-transfer mechanism, Including tentative identification of His 188 as the catalytic base. In support of this hypothesis, the CstII-H188A mutant is able to catalyze sialyl transfer from CMP-Neu5Ac to added anions such as azide and formate but not to its natural sugar acceptor lactose. Complementing this work, NMR spectroscopy was used to investigate the Structure and dynamics of CstII and to measure the intrinsic pK(a) value of His 188 for comparison with the pK(a) determined from the pH-dependent k(cat)/K-M of the enzyme. By systematically introducing point mutations at the subunit interfaces, two active monomeric variants, CstII-F121D and CstII-Y125Q, were obtained and characterized. In contrast to the wild-type tetramer, the monomeric CstII variants yielded good quality H-1/N-15-HSQC and H-1/C-13-methyl-TROSY NMR spectra. However, the absence of signals from approximately one-half of the amides in the H-1/N-15-HSQC spectra of both monomeric forms suggests that the enzyme undergoes substantial conformational exchange on a millisecond to microsecond time scale. The histidine pK(a) values of CstII-F121D in its apo form were measured by monitoring the pH-dependent chemical shifts of [C-13(epsilon l)]histidine, biosynthetically incorporated into the otherwise uniformly deuterated protein. Consistent with its proposed catalytic role, the site-specific pK(a) value similar to 6.6 of His 188 matches the apparent pK(a) value similar to 6.5 governing the pH dependence of k(cat)/K-M for CstII toward CMP-Neu5Ac in the presence of saturating acceptor substrate.},
	keywords = {20S PROTEASOME, CHEMICAL RESCUE, CRYSTAL-STRUCTURE, GANGLIOSIDE MIMICS, LABELING STRATEGY, MILLER-FISHER-SYNDROMES, SIALIC-ACID, STRUCTURAL-ANALYSIS, SUBSTRATE-ANALOG, TRANS-SIALIDASE},
	isbn = {0006-2960},
	url = {<Go to ISI>://000271950900011},
	author = {Chan, P. H. W. and Lairson, L. L. and Lee, H. J. and Wakarchuk, W. W. and Strynadka, N. C. J. and Withers, S. G. and McIntosh, L. P.}
}
@article {1147,
	title = {Calorimetric study on self-assembling of two kinds of monometallic nanoparticles in solution},
	journal = {Journal of Thermal Analysis and Calorimetry},
	volume = {81},
	number = {3},
	year = {2005},
	note = {ISI Document Delivery No.: 962VGTimes Cited: 4Cited Reference Count: 233rd International Symposium on New Frontiers of Thermal Studies of MaterialsNOV 28-30, 2004Tsukuba, JAPANJSCTA, Univ Tsukuba, Grad Sch Pure \& Appl Sci, Soc Promot Calorimetry \& Thermal Anal, Ibaraki, Sci \& Technol Promot Fdn},
	month = {Aug},
	pages = {523-527},
	type = {Proceedings Paper},
	abstract = {Recently, we have reported a noble method of preparing Ag/Rh bimetallic nanoparticles with a pseudo-core/shell structure. We simply mix the dispersions of poly(N-vinyl-2-pyrrolidone)(PVP)-protected Ag and Rh nanoparticles in solution at room temperature. We found that the mixture of dispersions forms bimetallic nanoparticles in a pseudo-core/shell structure on standing. We call this process the {\textquoteright}self-assembling{\textquoteright} or {\textquoteright}self-organizing{\textquoteright}. In this study we seek for a thermodynamic driving force for this process by determining the enthalpy of the interaction among three pairs of nanoparticles by isothermal titration calorimetry (ITC). The results indicate that the interaction between each pair is strongly exothermic, and that among the pairs studied here the strength of the exothermic interaction is in the order of Ag/Pt<Ag/Pd<Ag/Rh.},
	keywords = {bimetallic nanoparticles, calorimetric method, CATALYTIC-ACTIVITY, CLUSTERS, CORE-SHELL NANOPARTICLES, core/shell structure, GROWTH, isothermal titration calorimetry, metal nanoparticle, NUCLEATION, palladium, PD, platinum, REDUCTION, rhodium, self-assembling, SELF-ORGANIZATION, silver, STRUCTURAL-ANALYSIS},
	isbn = {1388-6150},
	url = {<Go to ISI>://000231760500004},
	author = {Kanemaru, M. and Shiraishi, Y. and Koga,Yoshikata and Toshima, N.}
}
@article {1290,
	title = {Spontaneous formation of core/shell bimetallic nanoparticles: A calorimetric study},
	journal = {Journal of Physical Chemistry B},
	volume = {109},
	number = {34},
	year = {2005},
	note = {ISI Document Delivery No.: 959DQTimes Cited: 23Cited Reference Count: 41},
	month = {Sep},
	pages = {16326-16331},
	type = {Article},
	abstract = {We showed recently that low entropy core/shell structured nanoparticles form spontaneously from the physical mixture of a dispersion of Ag nanoparticles and that of another noble metal (Rh. Pd, or Pt) at room, temperature. Here we use isothermal titration calorimetry (ITC) and show that the initial step of such a spontaneous process is strongly exothermic. When the alcohol dispersion of poly(N-vinyl-2-pyrrolidone) (PVP)-protected Rh nanoparticles (average diameter 2.3 nm) was titrated into the alcoholic dispersion of PVP-protected Ag nanoparticles, a strong exothermic enthalpy change, Delta H. was observed: Delta H = -908 kJ/mol for Ag(S) nanoparticle (average diameter 10.8 nm) and -963 kJ/mol for Ag(L) nanoparticles (average diameter 22.5 nm). The strength of interaction increases in the order of Rh/Ag > Pd/Ag > Pt/Ag. This strong exothermic interaction is considered as a driving force to from low entropy bimetallic nanoparticles by simple mixing of two kinds of monometallic nanoparticles. We show also that exothermic interactions occur between a pair of noble metal nanoparticles themselves by using ITC.},
	keywords = {ABSORPTION FINE-STRUCTURE, BINDING, CATALYTIC-ACTIVITY, CLUSTERS, CORE-SHELL, GOLD NANOPARTICLES, isothermal titration calorimetry, NANOPARTICLES, PD, REDUCTION, STRUCTURAL-ANALYSIS},
	isbn = {1520-6106},
	url = {<Go to ISI>://000231497500015},
	author = {Toshima, N. and Kanemaru, M. and Shiraishi, Y. and Koga,Yoshikata}
}
