Structural component of the T=16 icosahedral capsid. The capsid is composed of pentamers and hexamers of major capsid protein/MCP, which are linked together by heterotrimers called triplexes. These triplexes are formed by a single molecule of triplex protein 1/TRX1 and two copies of triplex protein 2/TRX2. Additionally, TRX1 is required for efficient transport of TRX2 to the nucleus, which is the site of capsid assembly (By similarity). Prevents also necroptosis and extrinsic apoptosis by sequestering host ZBP1 into large, insoluble supercomplexes and impairing its ability to interact with RIPK3 (PubMed:32649716). Interacts with TRX2, MCP and capsid vertex component 2/CVC2 (By similarity). Self-assembles into homo-oligomeric amyloid fibrils (PubMed:32649716). Interacts with host ZBP1; this interaction prevents host necroptosis and extrinsic apoptosis (PubMed:32649716). Interacts with host RIPK3 (PubMed:32649716). Belongs to the herpesviridae TRX1 protein family.