title: Trifluoroacetic acid as excipient destabilizes melittin causing the selective aggregation of melittin within the centrin-melittin-trifluoroacetic acid complex.
abstract: Trifluoroacetic acid (TFA) may be the cause of the bottleneck in high resolution structure determination for protein-peptide complexes. Fragment based drug design often involves the use of synthetic peptides which contain TFA (excipient). Our goal was to explore the effects of this excipient on a model complex: centrin-melittin-TFA. We performed Fourier transform infrared, two-dimensional infrared correlation spectroscopies and spectral simulations to analyze the amide I'/I'* band for the components and the ternary complex. Melittin (MLT) was observed to have increased helicity upon its interaction with centrin, followed by the thermally induced aggregation of MLT within the ternary complex in the TFA presence.
authors.forename: Belinda
authors.initials: B
authors.lastname: Pastrana-Rios
authors.affiliation: Department of Chemistry, University of Puerto Rico , Mayagüez Campus, Call Box 9019, Mayagüez, Puerto Rico 00681, USA.
authors.forename: Liliana
authors.initials: L
authors.lastname: Del Valle Sosa
authors.affiliation: Department of Chemistry, University of Puerto Rico , Mayagüez Campus, Call Box 9019, Mayagüez, Puerto Rico 00681, USA.
authors.forename: Jorge
authors.initials: J
authors.lastname: Santiago