## 3 Results and Discussion
### Analysis of Plasmid Presence and Antibiotic Resistance Genes
#### 3.6.5 NRPS and PKS Gene Clusters
Protein XIJ17220 has two modules (KS-AT-KR/KS-AT-KR(X)), protein XIJ19137 includes one module (KS-AT-DH-KR), protein XIJ17219 comprises two modules (KS-AT/KS-AT-DH-KR), and protein XIJ17218 contains two modules (KS-AT-DH-KR/KS-AT-DH-KR-TE). An additional Type I PKS exists between XIJ17222 and XIJ17223, originally found in the contig with 3428 amino acids, comprising two modules (KS-AT-KR/KS-AT-DH-ER-KR). However, in the GenBank annotation, it is divided into a Type I PKS with 2156 amino acids and six small protein fragments. Further sequence reanalysis and re-annotation of this region appear necessary. In addition, three P450 proteins are present consecutively downstream of the modular PKS cluster. Upstream of the Type I PKS cluster, we identified genes showing homology to queuosine biosynthesis genes (Figure S20, Table S29). However, unlike typical operon-like clusters, these queuosine biosynthesis genes are scattered throughout the region, with 6-carboxytetrahydrofuran synthetase QueD (protein 2813), GTP cyclohydrolase I (FolE, protein 2814), 7-cyano-7-deazaguanine synthase QueC (protein 2820), and 7-carboxy-7-deazaguanine synthase QueE (protein 2821) being dispersed. Given the absence of a densely packed queuosine BGC, we focused on the nucleoside toyocamycin BGC, which contains the queuosine precursor (Q\({}_{0}\)) structure [72]. As expected, the toyocamycin BGC exhibited high amino acid sequence homology with the queuosine biosynthesis proteins FolE, QueC, \begin{table}
\begin{tabular}{c c c c} \hline \hline
**GenBank** & **Putative Functions** & \begin{tabular}{c} **Venemycin (Identity/** \\ **Similarity**) \\ \end{tabular} & \begin{tabular}{c} **Kendomycin (Identity/** \\ **Similarity**) \\ \hline XIJ19095 & Transcriptional regulator & & \
\begin{tabular}{c} Ken21 (33.73\%/50.00\%) \\ \end{tabular} \\ XIJ16057 & Enoyl-CoA-hydratase DpgD & VemD 68.00\%/79.64\%) & Ken27 (73.33\%/79.63\%) \\ XIJ16058 & Enoyl-CoA hydratase/isomerase DpgC & VemC (54.24\%/63.56\%) & Ken4 (56.02\%/64.52\%) \\ XIJ16059 & 3,5-dihydroxypropylacetyl-CoA synthase DpgA & VemA (65.61\%/80.16\%) & Ken2 (68.04\%/77.06\%) \\ XIJ16070 & Transcriptional regulator & VemR (38.90\%/51.35\%) & \\ XIJ16076 & Enoyl-CoA-hydratase DpgB & VemD (31.51\%)/43.15\%) & Ken3 (49.60\%/62.30\%) \\ XIJ16077 & NAD(P)/FAD-dependent oxidoreductase & &
\begin{tabular}{c} Ken15 (46.40\%/62.18\%) \\ \end{tabular} \\ XIJ16079 & Thiamine pyrophosphate-binding protein & VemE (31.30\%/44.73\%) & Ken5 (34.57\%/46.36\%) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Comparison of homology between the biosynthetic enzymes of _Lentzea_ sp. JNUCC 0626 BCG region 10 and those of venemycin and kendomycin. QueD, and QueE. Specifically, the homologous proteins were identified as ToyD (67.5% identity), ToyM (41.9%), ToyB (62.4%), and ToyC (57.6%). However, in BGC region 16, no genes related to the ribose moiety linked to the Q\({}_{0}\) nitrogen-1 position of queuosine in toyocamycin were detected. Notably, between the FoLE, QueC, QueD, and QueE proteins, several proteins were identified, including a GTP cyclohydrolase I (XIJ17237), an ATP-grasp domain-containing protein (XIJ17238), an MPS transporter (XIJ17239), a methyltransferase (XIJ17240), a diaminobutyrate-2-oxoglutate transaminase (XIJ17241), and a 2-oxoglutate and iron-dependent oxygenase domain-containing protein (XIJ17242). The presence of these proteins suggests the potential for novel nucleoside antibiotic biosynthesis. BGC Region 17 Derived from _Lentzea_ sp. JNUCC 0626  
The antiSMASH analysis of the BGC 17 region of _Lentzea_ sp. JNUCC 0626 predicted 32% similarity to the BGC responsible for producing funisamine, a very long-chain fatty acid [73]. As shown in Figure S21 and Table S30, BGC 17 harbors a large PKS I cluster with 27 modules, spanning 10 multifunctional proteins from protein XIJ17345 to XIJ17358 and XIJ19142. Additionally, the KR domain of the 12 th module in protein XIJ17358 and all KR domains across the five modules in protein XIJ17357 were inferred to be inactive.