Crystals of the trp repressor-operator complex suitable for X-ray diffraction analysis

• Published in: The Journal of biological chemistry 1987-04, Vol.262 (10), p.4917-4921
• Main Authors: Joachimiak, A., Marmorstein, R.Q., Schevitz, R.W., Mandecki, W., Fox, J.L., Sigler, P.B.
• Format: Article
• Language: English
• Subjects: Bacterial Proteins; Biological and medical sciences; Crystallization; DNA, Bacterial - genetics; DNA, Bacterial - isolation & purification; Escherichia coli - analysis; Escherichia coli - genetics; Fundamental and applied biological sciences. Psychology; Molecular and cellular biology; Molecular genetics; Operator Regions, Genetic; operators; Repressor Proteins - genetics; Repressor Proteins - isolation & purification; repressors; Transcription Factors - isolation & purification; Transcription. Transcription factor. Splicing. Rna processing; X-Ray Diffraction
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)61284-0

Crystals of a simulated trp repressor-operator complex have been grown that are large enough and are sufficiently well ordered and durable to provide a high quality molecular image of this regulatory protein X DNA complex to better than 3-A resolution. The “operator” consists of a 2-fold rotationally symmetric 18-base pair duplex that is extended by a dT residue at both 5′-termini. This system exhibits extensive crystal polymorphism. The crystal form and diffraction properties are very sensitive to the length and terminal structure of the operator fragment, as well as the type and concentration of multivalent ions. When combined with the experience reported by others, our results do not support a consistent strategy for crystallization of protein X DNA complexes.