@article {1368,
	title = {Calcium ion exchange in crystalline gelsolin},
	journal = {Journal of Molecular Biology},
	volume = {357},
	number = {3},
	year = {2006},
	note = {ISI Document Delivery No.: 030IYTimes Cited: 6Cited Reference Count: 24},
	month = {Mar},
	pages = {773-782},
	type = {Article},
	abstract = {Gelsolin is a calcium and pH-sensitive modulator of actin filament length. Here, we use X-ray crystallography to examine the extraction and exchange of calcium ions from their binding sites in different crystalline forms of the activated N and C-terminal halves of gelsolin, G1-G3 and G4-G6, respectively. We demonstrate that the combination of calcium and low pH activating conditions do not induce conformational changes in G4-G6 beyond those elicited by calcium alone. EGTA is able to remove calcium ions bound to the type I and type II metal ion-binding sites in G4-G6. Constrained by crystal contacts and stabilized by interdomain interaction surfaces, the gross structure of calcium-depleted G4-G6 remains that of the activated form. However, high-resolution details of changes in the ion-binding sites may represent the initial steps toward restoration of the arrangement of domains found in the calcium-free inactive form of gelsolin in solution. Furthermore, bathing crystals with the trivalent calcium ion mimic, Tb3+, results in anomalous scattering data that permit unequivocal localization of terbium ions in each of the proposed type I and type II ion-binding sites of both halves of gelsolin. In contrast to predictions based on solution studies, we find that no calcium ion is immune to exchange. (c) 2006 Elsevier Ltd. All rights reserved.},
	keywords = {actin, ACTIN MONOMER, ACTIVATION, apoptosis, BINDING-SITE, C-TERMINAL HALF, calcium activation, COMPLEX, CONFORMATIONAL CHANGE, DOMAINS, ELECTRON-DENSITY MAPS, gelsolin, IDENTIFICATION, MECHANISMS, protein crystallography},
	isbn = {0022-2836},
	url = {<Go to ISI>://000236629300008},
	author = {Chumnarnsilpa, S. and Loonchanta, A. and Xue, B. and Choe, H. and Urosev, D. and Wang, H. and Lindberg, U. and Burtnick, L. D. and Robinson, R. C.}
}
@article {891,
	title = {Structural basis of actin sequestration by thymosin-beta 4: implications for WH2 proteins},
	journal = {Embo Journal},
	volume = {23},
	number = {18},
	year = {2004},
	note = {ISI Document Delivery No.: 861IFTimes Cited: 48Cited Reference Count: 51},
	month = {Sep},
	pages = {3599-3608},
	type = {Article},
	abstract = {The WH2 (Wiscott - Aldridge syndrome protein homology domain 2) repeat is an actin interacting motif found in monomer sequestering and filament assembly proteins. We have stabilized the prototypical WH2 family member, thymosin-beta4 (Tbeta4), with respect to actin, by creating a hybrid between gelsolin domain 1 and the C-terminal half of Tbeta4 (G1-Tbeta4). This hybrid protein sequesters actin monomers, severs actin filaments and acts as a leaky barbed end cap. Here, we present the structure of the G1-Tbeta4: actin complex at 2Angstrom resolution. The structure reveals that Tbeta4 sequesters by capping both ends of the actin monomer, and that exchange of actin between Tb4 and profilin is mediated by a minor overlap in binding sites. The structure implies that multiple WH2 motif-containing proteins will associate longitudinally with actin filaments. Finally, we discuss the role of the WH2 motif in arp2/3 activation.},
	keywords = {actin, ARP2/3 COMPLEX, BETA-THYMOSINS, BINDING-PROTEINS, CRYSTAL-STRUCTURE, DNASE-I, F-ACTIN, MONOMERIC, NEGATIVE COOPERATIVITY, NMR-SPECTROSCOPY, NUCLEAR-MAGNETIC-RESONANCE, protein crystallography, SCAR, VCA, WASp, WH2},
	isbn = {0261-4189},
	url = {<Go to ISI>://000224409100003},
	author = {Irobi, E. and Aguda, A. H. and Larsson, M. and Guerin, C. and Yin, H. L. and Burtnick, L. D. and Blanchoin, L. and Robinson, R. C.}
}
