The progress of membrane protein structure determination

Abstract

The rate of membrane protein (MP) structure determination has been examined for the 18-year period following the publication of the first high-resolution crystal structure. The growth is solidly exponential, but lags behind the rate for soluble proteins during the equivalent time period.

Figure 1.

Cumulative totals of new structures since publication of the first high-resolution crystallographic structures. The data for soluble proteins (red squares) are from a letter written in 1978 by Richard Dickerson (http://www.rcsb.org/pdb/dickerson_letter.html). The data for MPs (solid blue circles) were compiled from data available at http://blanco.biomol.uci.edu/Membrane_Proteins_xtal.html. “New” MP structures includes the same protein from different organisms, but excludes structures of mutagenized versions of proteins already in the database. Structures that differ only by the substrate bound or by physiological state are also excluded. The solid curves are fits of the data to the equation m = exp(by), where m is the cumulative total of new structures and y is the number of years since the publication of the first structure. The parameter b = 0.289 and 0.242 for soluble and for MPs, respectively. The data for MPs suggest that there will be more than 100 structures some time in 2005.