Tec
hnological advances
have facilitated t
he generation of artificial proteins t
hat possess t
he capabilities of recognizingand binding to inorganic solids and/or controlling nucleation processes t
hat form inorganic solids. However, very littleis known regarding t
he structure of t
hese interesting polypeptides and
how t
heir structure contributes to function
ality.To address t
his deficiency, we report structural investigations of an artificial protein, p288, t
hat self-assembles andcontrols t
he nucleation of simple salts and organic compounds into dendrite-like crystals. Under aqueous conditionsat low pH and in t
he presence of
hig
h salt, p288 is conformationally labile and exists primarily as a random coilconformer in equilibrium wit
h ot
her undefined secondary structures, including polyproline type II and
![](/images/gifc<font color=)
hars/beta2.gif" BORDER=0 ALIGN="middle"> turn. We notet
hat p288 can fold into eit
her a partial
![](/images/gifc<font color=)
hars/beta2.gif" BORDER=0 ALIGN="middle"> strand (at neutral pH) or a predominantly
![](/images/gifc<font color=)
hars/alp
ha.gif" BORDER=0>
helical (in t
he presence of TFE)conformation. Solid-state
13C-
15N NMR experiments also reveal t
hat p288 in t
he lyop
hilized,
hydrated state possessessome degree of nonrandom coil structure. T
hese results indicate t
hat p288 is conformationally labile but can undergoconformational transitions to a more stable structure w
hen water solvent loss/displacement occurs and proteinconcentrations increase. We believe t
hat conformational instability and t
he ability to adopt different structures as afunction of different environmental conditions represent important molecular features t
hat impact p288 supramolecularassembly and crystal nucleation processes.