Skip to main content
ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Ruminant Diseases and Immunology Research » Research » Publications at this Location » Publication #362507

Research Project: Identification of Disease Mechanisms and Control Strategies for Bacterial Respiratory Pathogens in Ruminants

Location: Ruminant Diseases and Immunology Research

Title: Synthetic bovine NK-lysin-derived peptide (bNK2A) does not require intra-chain disulfide bonds for bactericidal activity

item Dassanayake, Rohana
item Nicholson, Eric
item Tatum, Fred

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/5/2019
Publication Date: 6/19/2019
Citation: Dassanayake, R.P., Falkenberg, S.M., Nicholson, E.M., Briggs, R.E., Tatum, F.M., Sharma, V.K., Reinhardt, T.A. 2019. Synthetic bovine NK-lysin-derived peptide (bNK2A) does not require intra-chain disulfide bonds for bactericidal activity. PLoS One. 14(6).

Interpretive Summary: Bovine respiratory disease complex (BRDC or shipping fever) is the leading cause of severe economic losses to the beef and dairy cattle industry in the United States. Bacterial pathogens involved in cattle respiratory diseases are normal inhabitants of the upper respiratory tract. Due to the emergence of antibiotic-resistant bacteria, there is a need for the identification and development of reagents for an alternative to antibiotics. Previously, we have tested and identified several small proteins (NK-lysins) which were highly effective against bacterial pathogens causing BRDC. In this study, two amino acids in one of the small proteins were replaced two different amino acids and again tested for its bacterial killing activity. Both original and modified small proteins were able to kill tested BRDC causing bacteria. Further studies are needed to assess whether small proteins tested in this study can be used for prophylaxis or treat cattle against bacteria causing respiratory diseases.

Technical Abstract: We studied whether bovine NK-lysin-derived peptide (bNK2A) forms disulfide bonds and whether disulfide bonds were essential for bNK2A antimicrobial activity. Two NK-lysin-derived peptides were synthesized: one with two original cysteines and an analog with cysteines substituted with two serines. Mass spectrometry revealed lack of disulfide bonds in original peptide while CD spectrophotometry showed both peptides have similar a-helical structures. Since both peptides were equally inhibitory to Histophilus somni, disulfide bonds appeared dispensable for bNK2A antibacterial activity.