Abstract
We observed gelation of a 23-residue peptide derived from the β-sheet domain of platelet factor-4 (PF424-46). The gels were primarily heterogeneous mixtures of 50-200 μm spherical aggregates in a less-dense gel matrix. Infrared and circular dichroism spectroscopies showed gelation involving the conversion of PF424-46 from random coil to β-sheet. We used aggregation-induced NMR resonance broadening to show that temperature, pH, and ionic strength influenced PF424-46 gelation rates. Under identical solution conditions, gel formation took days at T ≤ 20 °C but only 30 min at T ≥ 50 °C. Gelation was most rapid at pH values near the pKa of the central His35 residue. Increases in solution ionic strength reduced the critical gelation concentration of PF424-46. Our results suggest that PF424-46 gels by a process combining aspects of both heat-set and β-fibril gelation mechanisms.
Original language | English (US) |
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Pages (from-to) | 1225-1232 |
Number of pages | 8 |
Journal | Biomacromolecules |
Volume | 3 |
Issue number | 6 |
DOIs | |
State | Published - Nov 1 2002 |