Deep Sequencing of a Systematic Peptide Library Reveals Conformationally-Constrained Protein Interface Peptides that Disrupt a Protein-Protein Interaction.

Disrupting protein-protein interactions is difficult due to the large and flat interaction surfaces of the binding partners. The BLIP and BLIP-II proteins are unrelated in sequence and structure and yet each potently inhibit β-lactamases. High-throughput oligonucleotide synthesis was used to construct a 12,470-member library containing overlapping linear and cyclic peptides ranging in size from 6 to 21 amino acids that scan through the sequences of BLIP and BLIP-II.

KPC-2 β-lactamase enables carbapenem antibiotic resistance through fast deacylation of the covalent intermediate.

Serine active-site β-lactamases hydrolyze β-lactam antibiotics through the formation of a covalent acyl-enzyme intermediate followed by deacylation via an activated water molecule. Carbapenem antibiotics are poorly hydrolyzed by most β-lactamases owing to slow hydrolysis of the acyl-enzyme intermediate. However, the emergence of the KPC-2 carbapenemase has resulted in widespread resistance to these drugs, suggesting it operates more efficiently.

High-Resolution Mapping of Human Norovirus Antigens via Genomic Phage Display Library Selections and Deep Sequencing.

Norovirus (NoV) infections are a leading cause of gastroenteritis. The humoral immune response plays an important role in the control of NoV, and recent studies have identified neutralizing antibodies that bind the capsid protein VP1 to block viral infection. Here, we utilize a NoV GI.

Mapping Protein-Protein Interaction Interface Peptides with Jun-Fos Assisted Phage Display and Deep Sequencing.

Protein-protein interactions govern many cellular processes, and identifying binding interaction sites on proteins can facilitate the discovery of inhibitors to block such interactions. Here we identify peptides from a randomly fragmented plasmid encoding the β-lactamase inhibitory protein (BLIP) and the Lac repressor (LacI) that represent regions of protein-protein interactions. We utilized a Jun-Fos-assisted phage display system that has previously been used to screen cDNA and genomic libraries to identify antibody antigens.

Reduced Susceptibility of Streptococcus pyogenes to β-Lactam Antibiotics Associated with Mutations in the Gene Is Geographically Widespread.

Recently, two related strains with reduced susceptibility to ampicillin, amoxicillin, and cefotaxime, antibiotics commonly used to treat infections, were reported. The two strains had the same nonsynonymous (amino acid-substituting) mutation in the gene, encoding penicillin-binding protein 2X (PBP2X). This concerning report led us to investigate our library of 7,025 genome sequences of type , , and clinical strains recovered from intercontinental sources for mutations in We identified 137 strains that, combined, had 37 nonsynonymous mutations in 36 codons in Although to a lesser magnitude than the two previously published isolates, many of our strains had decreased susceptibility to multiple beta-lactam antibiotics.