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RAFAEL GIRALDO SUÁREZ AN. R. ACAD. NAC. FARM.

ABSTRACT

Roger Kornberg and RNApol II: unveiling the mechanism of ribonucleic
acid synthesis half a century after Severo Ochoa and his polynucleotide

phosphorylase

The Nobel Prize in Chemistry 2006 has been awarded to Prof. Roger Kornberg,
Head of the Department of Structural Biology, Stanford CA, USA. Prof. Kornberg
has been leading along years an exhaustive and rigorous research effort on RNApol
II, the protein complex responsible for the synthesis of messenger RNA in
eukaryotic cells. By means of biophysical approaches, X-ray crystallography in
particular, his work shows how ten of the twelve protein subunits of the whole
enzyme are coordinated in order to melt the two DNA strands, recognize the first
ribonucleotide to be incorporated on the template chain to be transcribed and
catalyze polymerization of successive nucleotide building blocks with astonishing
fidelity and processivity. Nearly half a century after the pioneering in vitro synthesis
of RNA by Severo Ochoa, the work now awarded unveils, with a wealth of intimate
details, the function of the macromolecular machinery essential for gene expression.

Keywords: Nobel Prize Chemistry 2006.—Roger Kornberg.—RNApol II.—mRNA
synthesis.—X-ray crystallography.

INTRODUCCIÓN AL PROBLEMA BIOLÓGICO

La transmisión de la información genética es, junto con el esta-
blecimiento de un metabolismo energético y la compartimentaliza-
ción mediante membranas, uno de los principios definitorios de la
vida (1). El llamado «dogma central» de la Biología Molecular, for-
mulado por vez primera por Francis Crick para establecer el flujo de
información entre biomoléculas (para una perspectiva histórica,
véase ref. 2), asigna una posición central al ácido ribonucleico (ARN).
En su formulación más simple:

Es decir, la información almacenada en las porciones codificantes
(genes) del ácido desoxirribonucleico (ADN) es transferida a una ma-
cromolécula intermedia (el ARN mensajero, ARNm) que es finalmen-

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