Section 3.1.7. Reprise

We have reached a point where it is possible to use recombinant DNA techniques to produce most proteins in quantities sufficient for crystallography. Both high-level expression systems and methods for making defined modifications of recombinant proteins vastly simplify the process of purification. This has played a direct and critical role in the ability of crystallographers to produce an astonishing array of new and exciting protein structures. We are beginning to come to grips with the next level of the problem: using the ability to modify the sequence of proteins to improve their crystallization properties. This is a difficult problem; however, there are already notable, if hard won, successes. It would appear that the marriage of genetic engineering and crystallography – clearly a case in which opposites attract – has been a happy union. This is entirely for the good. Collaborations between specialists in these disciplines have led to the solution of problems too difficult for any individual armed only with the skills of one or the other partner. It is important that genetic engineering be fully integrated into future crystallographic efforts, either directly within the crystallography laboratory or through close collaborations. There yet remain formidable problems in protein structure and function that will require all the combined talents of the most skilled practitioners of these arcane arts.