Great news for biochemists, biologists and structural biologists—more than 50,000 protein expression plasmids and almost 100 empty vectors are now available through the PSI:Biology-Materials Repository 
. This includes about 900 membrane protein plasmids, and we expect this number—plus that for human proteins—to grow in the coming months.
The repository has carefully collected, maintained and annotated these materials generated by scientists involved in the Protein Structure Initiative. In addition, it has developed and optimized the empty vectors for producing proteins in bacteria, yeast and cell-free systems. For a modest charge, you can order the plasmids and vectors from the online catalog .
Many of the plasmids represent proteins whose crystal structures have been determined but whose biological functions are not yet known. Search the repository or use the Functional Sleuth to find out if the structure of your favorite protein or a similar one has already been determined.
If you can’t locate the plasmids you need in the PSI collection, you might search the larger DNASU plasmid repository , which houses the PSI:Biology Materials Repository. This central repository offers plasmids from hundreds of organisms and special collections, including human kinases, the Thermotoga maritime genome and a new set of 180 glycoenzymes.