Wayne A. Hendrickson, PhD
Howard Hughes Medical Institute Profile The program emphasizes three broad themes: structural biology of specific systems, methodology development, and biophysical principles of conformation, dynamics and assembly. Most of the macromolecules that we have under study relate to one or more of a few main biological subjects: cell surface interactions and signal transduction, immune response interactions, cellular responses to stress, genetic replication and transcription, carbohydrate recognition, and oxygen transport. Others have been chosen as subject for methodology development or for the analysis of general structural principles. Specific crystalline molecules that we are presently studying include the CD4 T-cell co-receptors, T-cell receptors, MHC molecules, superantigens, stem cell factor, fibroblast growth factor, insulin receptor, lymphocyte kinase, HIV envelope glycoprotein, FHIT, myelin Po, N- cadherin, ribonuclease H, carbamyl phosphate synthetase, UmuD, DnaK, streptavidin, and hemocyanin. The emphasis in methodology development is on crystallographic phase determination, structure refinement, computational methods, and synchrotron radiation research. Our research in phase determination centers on anomalous scattering--particularly, on methods for exploiting multiwavelength measurements of anomalous diffraction. Our effort to enhance procedures for stereochemically restrained refinement focuses on an improved treatment of the dynamic characteristics of molecules. A Crystallographic Workbench is being developed for integrated computing. And, with Howard Hughes support, we are developing synchrotron beamlines for macromolecular diffraction studies. Throughout our work we seek to gain insight into general principles as well as an understanding of specific processes. This is facilitated by methods that allow us to gain structural information in the greatest possible detail and accuracy. General properties that we are addressing include protein dynamics, conformational heterogeneity, metal binding in proteins, determinants of binding strength and specificity, assembly of protein interfaces, molecular symmetry, and bound water structure. Current Research 1. Anomalous scattering studies of macromolecular structure The overall objective of the proposed research is to effect a major enhancement in methods for macromolecular structure analysis. The overall objective is embodied in four specific aims: (1) We propose to continue our efforts to develop the theoretical basis and computational implementation of methods for exploiting the effects of anomalous scattering, particularly in multiwavelength anomalous diffraction (MAD) studies. (2) We propose to optimize the experimental procedures for conducting MAD experiments. For the most part these experiments will be conducted at the Hughes Synchrotron Resource that we are developing at Brookhaven National Laboratory. but we will also participate in the development of beamlines at other sources. (3) We propose to devise various means for introducing suitable scattering centers into macromolecules and to study the anomalous scattering characteristics of such centers. This work will emphasize general and convenient preparative procedures and especially strong scattering effects. (4) We propose to perform the methodology development in the course of applications to macromolecular crystal structures. National Institute of General Medical Sciences (4/1984-5/2004). 2. Structural Biology of G-Protein Coupled Receptors The overall objective of this proposal is to develop an atomic-level understanding of transmembrane signal transduction by G-protein coupled receptors (GPCRs). The ultimate aim of the proposal is to use x-ray crystallography to determine structures for GPCRs in relevant states, including complexes with natural signaling ligands, with pharmacological agonists and antagonists, and with signaling partner proteins, notably heterotrimeric G proteins. National Institute of General Medical Sciences (7/2003-6/2007).