**2. Results and Discussion**

#### *2.1. Sequence Analysis of FsAlyPL6*

The gene of FsAlyPL6 was cloned and analyzed from *Flammeovirga* sp. NJ-04. The open reading frame (ORF) consisted of 2238 bps and encoded a putative alginate lyase of 745 amino acid residues with a theoretical molecular mass of 83.09 kDa. According to the conserved domain analysis, the FsAlyPL6 contained an N-terminal catalytic domain (Met1-Asn366) and a C-terminal domain (Gln367-Lys745). Based on the sequence alignments shown in Figure 1, FsAlyPL6 shared the highest identity (45%) with AlyGC (BAEM00000000.1) from *Glaciecola chathamensis* S18K6T, which indicated FsAlyPL6 is a new member of family PL6. In addition, FsAlyPL6 contained three conserved regions "NG(G/A)E", "KS", and "R(H/S)G" (marked in Figure 1), which are involved in substrate binding and catalytic activity [12]. The alginate lyases of PL6 family can be divided into three subfamilies, namely subfamilies 1, 2, and 3. In order to confirm the subfamilies of FsAlyPL6, the phylogenetic tree was used to compare the sequence homology with alginate lyases from diverse subfamilies. As is shown in Figure 2, FsAlyPL6 clustered with representative enzymes of subfamily 1, which indicated FsAlyPL6 is a new member of the subfamily 1 alginate lyase.
