Virtuelle (Nano) Welten PDB Molecule of the Month 103: Dengue Virus

Building New Viruses

Dengue virus also makes several proteins that create new viruses once it is inside a cell. Two of the major ones are shown here. Both are multifunctional proteins with several enzymes strung together. The one on the left, NS5 from PDB entries 1l9k and 2j7w, contains a methyltransferase and a polymerase, and the one on the right, NS3 from PDB entry 2vbc, contains a protease and a helicase. Each of these enzymes performs a different part of the life cycle. The polymerase builds new RNA strands based on the viral RNA, the helicase helps to separate these strands, and the methyltransferase adds methyl groups to the end of them, protecting the RNA strands and coaxing the cell's ribosomes to create viral proteins based on them. The viral proteins are created in one long polyprotein chain, which is finally clipped into the functional units by the protease. The little chain colored blue is a portion of another viral protein, NS2B, that assists with the protease activity.

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