The use of MALDI-TOF-MS and in silico studies for determination of antimicrobial peptides' affinity to bacterial cells.

Several methods have been proposed for determining the binding affinity of antimicrobial peptides (AMPs) to bacterial cells. Here the utilization of MALDI-TOF-MS was proposed as a reliable and efficient method for high throughput AMP screening. The major advantage of the technique consists of finding AMPs that are selective and specific to a wide range of Gram-negative and -positive bacteria, providing a simple reliable screening tool to determine the potential candidates for broad spectrum antimicrobial drugs. As a prototype, amp-1 and -2 were used, showing highest activity toward Gram-negative and -positive membranes respectively. In addition, in silico molecular docking studies with both peptides were carried out for the membranes. In silico results indicated that both peptides presented affinity for DPPG and DPPE phospholipids, constructed in order to emulate an in vivo membrane bilayer. As a result, amp-1 showed a higher complementary surface for Gram-negative while amp-2 showed higher affinity to Gram-positive membranes, corroborating MS analyses. In summary, results here obtained suggested that in vitro methodology using MALDI-TOF-MS in addition to theoretical studies may be able to improve AMP screening quality.