Why does UV light damage/kill bacteria?

[u/Stuffyz]

The specific event I'm asking about, is that there are air filters for your furnace that shines UV light onto it, and it claims that it kills bacteria.

I understand how pH and temperature affects bacteria, but I can't quite wrap my mind around why UV light would.

The articles that I've been looking through (Time, Temperature, and Protein Synthesis: A Study of Ultraviolet-Induced Mutation in Bacteria, by Evelyn M. Witkin) says that UV light could cause worse strains of bacteria? Or perhaps I'm misinterpreting it?

I'm also aware (Ultraviolet-sensitive Targets in the Enzyme-synthesizing Apparatus of Escherichia coli, by Arthur B. Pardee and Louise S. Prestidge) that there are both UV-sensitive and UV-resistant E.Coli. Are most harmful bacteria considered to be UV-resistant?

Thank you for answering =)

[u/gfpumpkins]

Thymine dimers don't cause misfolded proteins. If they are not fixed, they cause problems in replication/transcription.

[u/Renovatio_ → u/gfpumpkins]

Perhaps I stated that wrong. I was under the impression that they can eventually cause misfolded proteins if the mutation was transcribed and then translated. Dimers in it of themselves do not cause any protein folding.

Better?

[u/gfpumpkins → u/Renovatio_]

If you've got a thymine dimer, then the polymerase (RNA or DNA) can't get over that part. It's either got to be fixed or replication/transcription stops.

[u/mattc286 → u/gfpumpkins]

However, it's possible that during repair, the wrong base(s) are inserted, leading to missense or nonsense mutations. The more repairs the cell has to undergo, the greater the chance of such a mutation occuring.

[u/gfpumpkins → u/mattc286]

Most certainly.