| Abstract
| - Technological advances have facilitated the generation of artificial proteins that possess the capabilities of recognizingand binding to inorganic solids and/or controlling nucleation processes that form inorganic solids. However, very littleis known regarding the structure of these interesting polypeptides and how their structure contributes to functionality.To address this deficiency, we report structural investigations of an artificial protein, p288, that self-assembles andcontrols the nucleation of simple salts and organic compounds into dendrite-like crystals. Under aqueous conditionsat low pH and in the presence of high salt, p288 is conformationally labile and exists primarily as a random coilconformer in equilibrium with other undefined secondary structures, including polyproline type II and β turn. We notethat p288 can fold into either a partial β strand (at neutral pH) or a predominantly α helical (in the presence of TFE)conformation. Solid-state 13C−15N NMR experiments also reveal that p288 in the lyophilized, hydrated state possessessome degree of nonrandom coil structure. These results indicate that p288 is conformationally labile but can undergoconformational transitions to a more stable structure when water solvent loss/displacement occurs and proteinconcentrations increase. We believe that conformational instability and the ability to adopt different structures as afunction of different environmental conditions represent important molecular features that impact p288 supramolecularassembly and crystal nucleation processes.
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