## 3 Discussion  
Some Plantaricin 149 analogs previously explored showed antimicrobial activity, but this was not investigated thoroughly. When such activity was observed, it occurred at high concentrations. An Fmoc protecting group at the N-terminus of the peptide is noteworthy and seems to have increased the activity of this bacteriocin [9]. This group is used in organic synthesis to protect amines, and has hydrophobic characteristics. Thus, the first peptide to be tested was Fmoc-Pln149, the original sequence of this bacteriocin with the Fmoc-protecting group. This peptide was active against all the strains tested, but with hemolytic activity occurring at much lower concentrations than the action against pathogenic bacteria. Fmoc-Pln149(6-22) lacked the N-terminal portion of the peptide, based on studies showing that this region does not contribute to antimicrobial activity in PlnA [8]. Fmoc-Pln149(6-22) peptide showed activity against all tested strains. Despite acting at higher concentrations than those of Fmoc-Pln149, its hemolytic activity was attenuated. Therefore, the Fmoc group is not solely responsible for the hemolytic activity, as the amino-acid sequence also influenced this. The peptide Pln149-PEP20 proposed in this paper was based on Fmoc-Pln149(6-22) but used alpha-helix projection and altered the amino acids to obtain a well-defined amphipathic secondary structure. This peptide showed a \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Replicate**} & \multirow{2}{*}{
\begin{tabular}{c} **Sequencing** \\ **Coverage \({}^{*}\)** \\ \end{tabular} } & \multirow{2}{*}{**N50**} & \multirow{2}{*}{**Mutation**} & \multirow{2}{*}{**Change**} & \multirow{2}{*}{**Altered Protein**} \\ \hline \multirow{10}{*}{A} & & & G \textgreater{} C & Ser126 Thr & \\  & & & A \textgreater{} G & Thr128 Ala & \\  & & & CT \textgreater{} GC & Thr137 Ser & \\  & & & A \textgreater{} T & Thr139 Ser & \\  & & & T \textgreater{} AACC & Asn ** & \\  & & & AAAT \textgreater{} GGTG & Asn146 Val & \\  & & & A \textgreater{} C & Lys150 Thr & \\  & & & TT \textgreater{} CA & Ile154 Thr & \\  & & & C \textgreater{} A & Pro162 Thr & \\  & & & GGA \textgreater{} TTG & Gly164 Leu & \\  & & & CT \textgreater{} GC & Ala168 Gly & \\  & & & TT \textgreater{} CA & Ile169 Thr & \\  & & & GAT \textgreater{} TCA & Asp171 Ser & \\  & & & 517\_518 Ins *** & *** & \\  & & & T \textgreater{} CACA & Thr *** & \\  & & & GACA \textgreater{} TGTG & Thr176 Val & \\  & & & TA \textgreater{} GG & Asn180 Asp & \\  & & & A \textgreater{} G & Thr265 Ala & \\ \hline \multirow{10}{*}{B} & & & T \textgreater{} AACC & Asn *** & \\  & & & AAAAT \textgreater{} GGTG & Asn243 Val & \\  & & & A \textgreater{} C & Lys247 Thr & \\  & & & TT \textgreater{} CA & Ile251 Thr & \\  & & & C \textgreater{} A & Pro259 Thr & \\ \hline C & 141\(\times\) & 7,603 & TA \textgreater{} GG & Asn164 Asp & \textgreater{} Ig-like domain-containing protein \\ \hline \hline \end{tabular}  
* * Coverages of the initial strains were 173\(\times\), 200\(\times\), and 178\(\times\), respectively; ** Insertion of Asn between Gly144 and Leu145; *** Insertion of ACA between nucleotides 517 and 518 of the gene encoding the protein, resulting in Val173 deletion and insertion of Asp and Ile; *** Insertion of Thr between Val173 and Ala174; *** Insertion of Asn between Gly241 and Leu242.  
\end{table} 
Table 7: Comparison between the initial and final strains of the _A. baumannii_ ATCC 19606 in vitro selection with Pln149-PEP20. significant improvement compared with previously published peptides because it is not only bactericidal at lower concentrations, but it also significantly reduces the hemolytic rate. Therefore, Pln149-PEP20 was more advantageous than the parent molecule, and its antimicrobial activity was characterized in this study. The investigation of Pln149-PEP20 allowed us to determine the peptide's antimicrobial activity characteristics. The PAE results indicated that, even after the serum concentration decreased, the peptide continued to prevent bacterial growth [27].