Just a thought: I wonder if the virus uses some form of redundancy encoding like certain RAID or file XOR systems use. I wonder if RNA/DNA has a checksum or data correction code somewhere?
It would be really neat if this virus does something like that. It might be why the 5th viral component is not required.
It actually is likely the opposite. Many viruses deliberately avoid checksumming and error correcting, as that's how it generates better modular parts - through errors and variation. Some viruses like HPV actively shut down their host's error-correction equipment, so that they may be more effective (why HPV infections greatly increase chance of cancer). If you have a multi-part system where your factory is producing literally billions of variants of each, and you want better parts, one way to do that is to have each part be slightly different. Those that naturally work best together will go on to be more, well, virulent.
Along with that, one of the reasons HIV is so hard to design a vaccine for is it's absurdly high error rate, which drives a huge amount of genetic diversity even within-host.
> I wonder if RNA/DNA has a checksum or data correction code somewhere?
You may consider CRISPR mechanism that Bacteria use to defend themselves against mutations introduced by the invading viruses as sort of data corerction.
As for greater organisms, it seems that preferable approach is to have copies of single genes in case. Apparently some species are more resistant to cancer to other due to number of anti-cancerous genene they posses in their DNA. Phenomena is known as Peto's Paradox:
It would be really neat if this virus does something like that. It might be why the 5th viral component is not required.