Antibiotics are tiny chemicals that can kill bacteria, and their use can wipe out almost all the individuals of a bacterial population. How do bacteria acquire antibiotic resistance?
In a recent study, investigators determined the mechanisms behind methicillin resistance in a strain of common skin bacteria.1 The antibiotic methicillin kills by attaching to a certain site on bacterial ribosomes, jamming their activity. Ribosomes are molecular machines required to build proteins.
In the wild strain of these bacteria, a protein named RlmN adds a methyl group to carbon number two of the 2503rd ribosomal nucleic acid. Thus, RlmN helps assemble the ribosome, which in turn assembles other proteins, including RlmN.
But in the resistant strain, a very similar protein named Cfr adds the methyl group to carbon number eight instead. This tiny shift keeps methicillin from “clogging” the ribosome and ultimately destroying the bacterium. The resistant bacteria have Cfr and they can therefore continue to survive, although their less-efficient ribosomes manufacture proteins more slowly.
In the researchers’ scenario, RlmN supposedly evolved into Cfr. But the actual changes from RlmN to Cfr involved a loss of information!2 RlmN had some flexible regions that ensured that the methyl group was added to carbon number two. Cfr no longer has these regions. That’s no help to big-picture evolution, which must account for the origin of all the critical spatial and “electrostatic surface potential” distributions in these proteins—without any intelligent source.1
Adaptive programming, not evolution, appears to be responsible for the ability of these bacteria to survive in methicillin. These bacteria are designed to adapt, designed by a living Creator God!
(excerpted from Brian Thomas, Antibiotic Resistance in Bacteria Shows Adaptive Design, Acts & Facts, July 2011, Institute for Creation Research)
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References (selected)
1. Boal, A. K. et al. Structural Basis for Methyl Transfer by a Radical SAM Enzyme. Science Express. Posted on sciencemag.org April 28, 2011, accessed April 28, 2011.
2. Thomas, B. Antibiotic Resistance in Bacteria Did Not Evolve. ICR News. Posted on icr.org May 10, 2011, accessed May 19, 2011.
Friday, July 29, 2011
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