Characterization of novel viral enzymes to be utilized in recycling of biomass

多糖降解酶包括壳聚糖酶、壳聚糖酶、β-1，3-葡聚糖酶、瓦尔-1和瓦尔-2，它们由绿病毒（Phycodnaviridae）编码。这些酶在感染过程中表达，并在病毒复制周期的初始阶段和最终阶段发挥作用。CVK 2（一种在日本京都分离的病毒）的vChti-1几丁质酶具有两个催化结构域的串联阵列，每个催化结构域显示不同的酶活性方式。两种大小不同的vChta-1壳聚糖酶通过通读机制从单个基因产生：具有病毒体靶向信号的较大蛋白质被掺入病毒颗粒中，在感染开始时起作用，而较小的蛋白质在感染后期表达，并在病毒释放之前帮助消化宿主细胞壁。cAL-1藻类溶解酶分解小球藻细胞壁，释放酸性糖，可能是糖醛酸。所有这些酶都被认为是协同作用，以消化宿主小球藻细胞壁的复杂结构和组成。

Polysaccharide-degrading enzymes including chariness, chitosanases, β-1, 3-glucanse, vAL-1, and vAL-2 are encoded by chloroviruses (Phycodnaviridae). These enzymes are expressed during infection and function at the initial stage as well as the final stage of the viral replication cycle. The vChti-1 chitinase of CVK2, a virus isolated in Kyoto, Japan, has a tandem array of two catalytic domains, each of which shows a different fashion of enzyme activity. Two size-different vChta-1 chitosanases are produced from a single gene by a read-through mechanism: the larger protein with a virion-targetting signal is incorporated into the virus particle, functioning at the beginning of the infection while the smaller protein is expressed late in infection and aids in the digestion of the host cell wall prior to the release of the viruses. The cAL-1 algal lytic enzyme digests the Chlorella cell wall, releasing acidic sugars, probably uronic acids. All of these enzymes are supposed to function cooperatively to digest complex structures and compositions of the host Chlorella cell wall.