Graduate School of Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama, 930-0194 (Japan).
Published: November 2014
AI Article Synopsis
Article Abstract
Managing protein-protein interactions is essential for resolving unknown biological events at the molecular level and developing drugs. We have designed and synthesized a side-chain-crosslinked helical peptides based on the binding domain of a pro-apoptotic protein (Bad) that induces programmed cell death. The peptide showed high helical content and bound to its target, Bcl-XL, more strongly than its non-crosslinked counterparts. When HeLa cells were incubated with the crosslinked peptide, the peptide entered the cytosol across the plasma membrane. The peptide formed a stable complex with Bcl-XL localized at the outer mitochondrial membrane, and this binding event caused the release of cytochrome c from the intermembrane space of mitochondria into the cytosol. This activated the caspase cascade: 70% of HeLa cells died by the apoptosis pathway (without evidence of necrosis).
Biochemistry and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India.
The quest for new approaches for generating novel bioactive designer proteins/peptides has continued with their success in various biomedical applications. Previously, we designed a 14-mer α-helical peptide with antimicrobial and antimycobacterial activities by employing a tandem repeat of the 7-mer, "KVLGRLV" human chemerin segment. Herein, we devised a new method of "sliding framework" with this segment to create amino acid scaffolds of varying sizes and sequences and explored the design of a peptide library with antibacterial and antimycobacterial activities.
Peptide stapling has emerged as a versatile approach in drug discovery to reinforce secondary structure elements especially α-helices and improve properties of linear bioactive peptides. Inspired by the prevalence of arginine in protein-protein and protein-DNA interfaces, we investigated guanidinium-stapling as a means to constrain helical peptides. Guanidinium stapling was readily achieved on solid support, utilizing two orthogonally protected lysine or unatural α-amino acid residues with an amino function.
Unlabelled: Proteolysis of hydrophobic helices is required for complete breakdown of every transmembrane protein trafficked to the lysosome and sustains high rates of endocytosis. However, the lysosomal mechanisms for degrading hydrophobic domains remain unknown. Combining lysosomal proteomics with functional genomic data mining, we identify Lysosomal Leucine Aminopeptidase (LyLAP; formerly Phospholipase B Domain-Containing 1) as the hydrolase most tightly associated with elevated endocytic activity.
The ultrashort peptide -fluorenylmethoxycarbonyl-phenylalanyl-phenylalanine (FmocFF) has been largely investigated due to its ability to self-assemble into fibrils (100 nm-μm scale) that can form a sample-spanning gel network. The initiation of the gelation process requires either a solvent switch (water added to dimethyl sulfoxide) or a pH-switch (alkaline to neutral) protocol, both of which ensure the solubility of the peptide as a necessary step preceding gelation. While the respective gel phases are well understood in structural and material characteristics terms the pregelation conditions are known to a lesser extent.
Noncanonical base pairs play an important role in enabling the structural and functional complexity of RNA. Molecular recognition of such motifs is challenging because of their diversity, significant deviation from the Watson-Crick structures, and dynamic behavior, resulting in alternative conformations of similar stability. Triplex-forming peptide nucleic acids (PNAs) have emerged as excellent ligands for the recognition of Watson-Crick base-paired double helical RNA.
