## 3 Results and Discussion
### Analysis of Plasmid Presence and Antibiotic Resistance Genes
#### 3.6.6 Other Gene Clusters
Notably, downstream of the minimycin-like BGC in L. jejunisis, there are four transporter genes aligned in the reverse transcriptional direction, while upstream, a dihydrofolate reductase family protein (protein XJJ10321) and a regulatory gene encoding an AAA family ATPase (protein XJJ10322) are transcribed in the opposite direction (Figure S25, Table S37). Further investigation is required to determine whether these genes play a role in the biosynthesis of minimycin-like compounds in L. jejunisis and their contribution to the overall metabolic pathway. Additionally, fermentation-based studies aimed at isolating natural products from _Lentzea_ sp. JNUCC 0626 will be essential to validate the biosynthetic potential of these gene clusters. This approach will not only confirm the production of minimycin-like compounds but also enhance the significance of this research by uncovering novel bioactive molecules with potential pharmaceutical applications. BGC Region 28 Derived from _Lentzea_ sp. JNUCC 0626  
Pyrroloquinoline quinone (PQQ) is a redox-active cofactor that has garnered significant attention in biotechnology and medicine due to its diverse biological roles. A particularly interesting aspect of PQQ is its biosynthetic pathway, which is encoded by a cluster of genes located in BGC region 28. These genes collaborate intricately, each playing a vital role in the synthesis of PQQ. The first key gene, pqqA, encodes a precursor peptide essential for PQQ synthesis, serving as the foundational substrate. Following this, pqqE functions as an S-adenosylmethionine (SAM)-dependent enzyme. It catalyzes a critical radical reaction that forms a bond between glutamic acid and tyrosine within the PqqA precursor. Meanwhile, pqqD contributes by protecting the PqqA precursor peptide and facilitating efficient reactions through its interaction with PqqE. As the process continues, pqqB takes on the role of promoting the structural modifications of PqqA, initiating the initial oxidation process. Subsequently, pqqC catalyzes the oxidative reactions required for forming the cyclic structure of PQQ, ultimately leading to the generation of a complete PQQ molecule. Finally, pqqF is involved in the final processing of the PQQ precursor, ensuring that the completed PQQ is prepared for export outside the cell [95]. The biosynthetic pathway is visually represented in Figure S26 and Table S38, highlighting the sequential actions of these proteins: XJJ10688 (PqqA) \(\rightarrow\) XJJ10691 (PqqE) \(\rightarrow\) XJ10690 (PqqD) \(\rightarrow\) XJ10692 (PqqB) \(\rightarrow\) XJJ10689 (PqqC) \(\rightarrow\) XJJ10687 (PqqF). Interestingly, adjacent to the pqqB gene in the PQQ operon of L. jejunisis, there exists a protein (XJJ10693) with high homology to the CdaR family transcriptional regulator. This gene may influence the expression of PQQ biosynthetic enzymes by binding to specific genes in the pathway, thus modulating transcriptional activation [96; 97]. The BCC linked to PQQ biosynthesis offers numerous potential applications. By leveraging PQQ's ability to generate electrochemical signalsthrough specific enzyme reactions, it holds promise in the development of biosensors. Moreover, functional foods containing PQQ could significantly enhance immune function, provide anti-aging benefits, and offer cardiovascular and neuroprotective effects, contributing to the advancement of nutraceuticalals and pharmaceuticals. In summary, future research endeavors should aim to deepen our understanding of the PQQ biosynthesis pathway. This knowledge will pave the way for genetic manipulation and enzyme engineering strategies to maximize PQQ production, ultimately facilitating its commercialization. BGC Region 29 Derived from _Lentza_ sp. JNUCC 0626  
In BGC region 29, an enzyme responsible for the biosynthesis of epsilon-poly-L-lysine (\(\varepsilon\)-PL), identified as protein XJ12648, has been located (Figure S27, Table S39). \(\varepsilon\)-PL is a polymer synthesized by NRPS and consists of 25-35 L-lysine residues linked by isopeptide bonds.