Posted on 11/16/2005 3:40:35 AM PST by snarks_when_bored
* 14:02 15 November 2005
* NewScientist.com news service
* Gaia Vince
A new microscope sensitive enough to track the real-time motion of a single protein, right down to the scale of its individual atoms, has revealed how genes are copied from DNA – a process essential to life.
The novel device allows users to achieve the highest-resolution measurements ever, equivalent to the diameter of a single hydrogen atom, says Steven Block, who designed it with colleagues at Stanford University in California.
Block was able to use the microscope to track a molecule of DNA from an E.coli bacterium, settling a long-standing scientific debate about the precise method in which genetic material is copied for use.
The molecular double-helix of DNA resembles a twisted ladder consisting of two strands connected by “rungs” called bases. The bases, which are known by the abbreviations A, T, G and C, encode genetic information, and the sequence in which they appear “spell out” different genes.
Every time a new protein is made, the genetic information for that protein must first be transcribed from its DNA blueprint. The transcriber, an enzyme called RNA polymerase (RNAP), latches on to the DNA ladder and pulls a small section apart lengthwise. As it works its way down the section of DNA, RNAP copies the sequence of bases and builds a complementary strand of RNA – the first step in a new protein.
“For years, people have known that RNA is made up one base at a time,” Block says. “But that has left open the question of whether the RNAP enzyme actually climbs up the DNA ladder one rung at a time, or does it move instead in chunks – for example, does it add three bases, then jump along and add another three bases.
Light and helium
In order to settle the question, the researchers designed equipment that was able to very accurately monitor the movements of a single DNA molecule.
Block chemically bonded one end of the DNA length to a glass bead. The bead was just 1 micrometre across, a thousand times the length of the DNA molecule and, crucially, a billion times its volume. He then bonded the RNAP enzyme to another bead. Both beads were placed in a watery substrate on a microscope slide.
Using mirrors, he then focused two infrared laser beams down onto each bead. Because the glass bead was in water, there was a refractive (optical density) difference between the glass and water, which caused the laser to bend and focus the light so that Block knew exactly where each bead was.
But in dealing with such small objects, he could not afford any of the normal wobbles in the light that occur when the photons have to pass through different densities of air at differing temperatures. So, he encased the whole microscope in a box containing helium. Helium has a very low refractive index so, even if temperature fluctuations occurred, the effect would be too small to matter.
One by one
The group then manipulated one of the glass beads until the RNAP latched on to a rung on the DNA molecule. As the enzyme moved along the bases, it tugged the glass bead it was bonded too, moving the two beads toward each together. The RNAP jerked along the DNA, pausing between jerks to churn out RNA transcribed bases. It was by precisely measuring the lengths of the jerks that Block determined how many bases it transcribed each time.
“The RNAP climbs the DNA ladder one base pair at a time – that is probably the right answer,” he says.
“It’s a very neat system – amazing to be able see molecular details and work out how DNA is transcribed for the first time,” said Justin Molloy, who has pioneered similar work at the National Institute for Medical Research, London. “It’s pretty incredible. You would never have believed it could be possible 10 years ago.”
Journal reference: Nature (DOI: 10.1038/nature04268)
It won't make any difference. You could have Behe knock on his door and say "Hi, I'm Mike Behe and the Designer is God" and he wouldn't believe it.
It's a problem with sneaking, twisting and lying. If you do it, you expect everyone is doing it too.
He won't answer you question either.
Nope. You have a comprehension problem, and a bad paint brush. Science is not at liberty to declare the ulimate cause behind physical matter as absolutely unattainable. You want science to say what it is not a liberty to say. You and your ilk would like to force science into your own little hermetically-sealed genie bottle.
Science is already very capable of identifying intelligence and design. In many cases the work of a craftsman can be scientfically analyzed to the extent the craftsman can be ascertained physically. In fact, in many cases it is very simple. From this it is hardly unreasonable to leave open the matter of how, or whether, there is a personal, intelligent designer in cases where it has not yet been identified.
You just blew your concept of ID out of the science arena.
Donkey Shine.
Wayne Newton's biggest hit?
Its only quote mining if you present it in such a way as to make it say something the original author did not intend.
Then why do you not believe what He says about creating and sustaining the world?
On the contrary, it is scientifically accurate to say all matter is ordered and genrrally behaves consistently with established physical laws. It may also be scientifically accurate to say God is responsible for it all. Science is free to explore the matter. Brain-tied ideologues are not.
"Then why do you not believe what He says about creating and sustaining the world?"
He hasn't told me about creating and sustaining the world.
BTW, I don't believe in Santa Claus either, but that is certainly not because I *hate* him. Your logic is seriously flawed.
Let me rephrase that so you can climb down off your rocking horse: Unlike you I am not inclined to rule certain things out when it comes to the practice of science.
You wanted to take my statement as if I were saying little green monkeys and elves should be considered a reasonable object of scientific pusrsuit. Well take that red herring and choke on it. If you insist that is the necessary logical result of my statement, then choke on it again.
Science is not at liberty to rule out the possibility that God really did create the heavens and the earth and sustains them. Nor is it at liberty to rule out the possibility that hypotheses can some day be formulated, tested, and observations made, to support that potential reality.
You can say "it's not scientific" to infer or make an intelligent designer a potential object of science till your blue in the face. Fine. Choke on that red herring a third time.
Have you not heard these words: "In the beginning God created the heavens and the earth?"
No. We see the object first, make inferences from there, and then pursue the knowledge that would confirm our inference. What do you mean "only because?" It's simple science, but science nevertheless.
"Have you not heard these words: "In the beginning God created the heavens and the earth?"
I read that in a book some people wrote.
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