Supramolecular Properties of the Proline-Rich γ -Zein N-Terminal Domain

Marcelo J. Kogan, Ionara Dalcol, Pau Gorostiza, Carmen Lopez-Iglesias, Ramon Pons, Miquel Pons, Fausto Sanz, Ernest Giralt
2002 Biophysical Journal  
Zeins are maize storages proteins that accumulate inside large vesicles called protein bodies. ␥-Zein lines the inner face of the protein body membrane, and its N-terminal proline-rich repetitive domain with the sequence (VHLPPP) 8 appears to be necessary for the accumulation of the protein within the organelle. Synthetic (VHLPPP) 8 adopts an amphipathic polyproline II conformation. In a preliminary recent work we used atomic force microscopy to study the surface organization of the octamer and
more » ... transmission electron microscopy to visualize aggregates of the peptide from aqueous solution. We previously envisioned two self-assembly models (i.e., the geometric and the micellar) that take into account the observed features. In the present work we studied in detail the self-assembly of the peptide in solution and found that the peptide is able to form cylindrical micelles. Fibrils formed on graphite are generated by assembly of solution micelles. Based on the results of these studies, we focused exclusively on the micellar model. To our knowledge we have characterized for the first time supramolecular aggregates of polyproline structures other than collagen. The spontaneous arrangement of (VHLPPP) 8 suggests a role for the N-terminal domain of ␥-zein in the process of the whole protein deposition in protein bodies.
doi:10.1016/s0006-3495(02)75243-0 pmid:12124299 pmcid:PMC1302221 fatcat:5eudhqr7cjesfnbaxcp2xnprw4