*4.6. ECD Calculation*

The calculations were performed using DFT on Gaussian 03, and the calculation details were follow strictly as described in literature [18]. Briefly, the calculations were performed by using the density functional theory (DFT) as carried out in the Gaussian 03 [19]. The preliminary conformational distribution search was performed using Frog2 online version [20]. Further geometrical optimization was performed at the B3LYP/6-31G(d) level. Solvent effects of methanol solution were evaluated at the same DFT level by using the SCRF/PCM method [21]. TDDFT [22–24] at B3LYP/6-31G(d) was employed to calculate the electronic excitation energies and rotational strengths in methanol, except compound **1** with calculation in chloroform.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/1660-3397/18/5/255/s1, Table S1: Oligonucleotide primers used in this study, Table S2: Deduced functions of ORFs in *xanq* biosynthetic pathway of strain 172205; Figure S1: Confirmation of enterocin gene cluster disruption by PCR, Figures S2–S8: HERESIMS, IR, 1D and 2D spectra of compound **1**, Figures S9–S16: HERESIMS, IR, 1D and 2D spectra of compound **2**, Figures S17–S24: HERESIMS, IR, 1D and 2D spectra of compound **3**, Figures S25–S32: HERESIMS, IR, 1D and 2D spectra of compound **4**, Figures S33–S40: HERESIMS, IR, 1D and 2D spectra of compound **5**. Figure S41. Comparison of genetic organization of *xanq* in strain 172205 and *xan* in *S. flavogriseus*.

**Author Contributions:** D.X. and K.H. designed the experiments; D.X. performed the experiments including fermentation, isolation and identification, as well as the bioassay test; E.T. helped and confirmed with the identification of part of compounds; F.K. performed the ECD calculations. D.X. wrote the paper, and the other authors revised the paper. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was partially supported by the National Key R&D Program of China (No. 2018YFC0311000), the National Natural Science Foundation of China (No. 31170467) and EU FP7 project PharmaSea (312184).

**Conflicts of Interest:** The authors declare no conflict of interest.
