title: X-ray crystallography and its impact on understanding bacterial cell wall remodeling processes.
abstract: The molecular structure of matter defines its properties and function. This is especially true for biological macromolecules such as proteins, which participate in virtually all biochemical processes. A three dimensional structural model of a protein is thus essential for the detailed understanding of its physiological function and the characterization of essential properties such as ligand binding and reaction mechanism. X-ray crystallography is a well-established technique that has been used for many years, but it is still by far the most widely used method for structure determination. A particular strength of this technique is the elucidation of atomic details of molecular interactions, thus providing an invaluable tool for a multitude of scientific projects ranging from the structural classification of macromolecules over the validation of enzymatic mechanisms or the understanding of host-pathogen interactions to structure-guided drug design. In the first part of this review, we describe essential methodological and practical aspects of X-ray crystallography. We provide some pointers that should allow researchers without a background in structural biology to assess the overall quality and reliability of a crystal structure. To highlight its potential, we then survey the impact X-ray crystallography has had on advancing an understanding of a class of enzymes that modify the bacterial cell wall. A substantial number of different bacterial amidase structures have been solved, mostly by X-ray crystallography. Comparison of these structures highlights conserved as well as divergent features. In combination with functional analyses, structural information on these enzymes has therefore proven to be a valuable template not only for understanding their mechanism of catalysis, but also for targeted interference with substrate binding.
authors.affiliation: Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Straße 4, 72076 Tübingen, Germany.
authors.forename: Felix Michael
authors.initials: FM
authors.lastname: Büttner
authors.affiliation: Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Straße 4, 72076 Tübingen, Germany.
authors.forename: Michaela
authors.initials: M
authors.lastname: Renner-Schneck
authors.affiliation: Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Straße 4, 72076 Tübingen, Germany; Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN, USA. Electronic address: thilo.stehle@uni-tuebingen.de.
authors.forename: Thilo
authors.initials: T
authors.lastname: Stehle
mesh_terms: D001419:Bacteria / Q000201:enzymology* / Q000378:metabolism; D002473:Cell Wall / Q000201:enzymology* / Q000378:metabolism*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000737:chemistry* / Q000378:metabolism*; D011487:Protein Conformation
chemical_list: D009238:N-Acetylmuramoyl-L-alanine Amidase
keywords: Bacterial cell wall; Complex structures; N-acetylmuramoyl-l-alanine amidases; Peptidoglycan; Structural biology; X-ray crystallography