Title: Structural insights into the mechanism of four-coordinate Cob(II)alamin formation in the active site of the Salmonella enterica ATP:Co(I)rrinoid adenosyltransferase enzyme: critical role of residues Phe91 and Trp93. Biochemistry, 51, 9647–9657.
ATP:Co(I)rrinoid adenosyltransferases (ACATs) bind five-coordinate cobalamin to transiently form four-coordinate cobalamin, which raises the cofactor’s reduction potential. This allows cobalamin to be reduced by an electron donor and react with bound ATP to form coenzyme B12 and PPPi. Shown here is the structure of an ACAT from S. enterica, CobA, binding five-coordinate cobalamin with MgATP (left) and four-coordinate cobalamin with MgATP (right) at 2.0Å resolution. Residues Trp93 and Phe91 (gold) are responsible for forming four-coordinate cobalamin by displacing the cofactor’s alpha-ligand. These residues are positioned directly under cobalamin four-coordinate site, approximately 8Å closer to the cofactor than their position in the five-coordinate site. This figure was made using PyMol.
Journal of Biological Chemistry: 2008
Title: Structural and Functional Characterization of the TRI101 Trichothecene 3-O-Acetyltransferase from Fusarium sporotrichioides and Fusarium graminearum: Kinetic Insights to Combating Fusarium Head Blight. Journal of Biological Chemistry, 283, 1660-1660.
Fusarium Head Blight (FHB) is a serious plant disease caused by fungal species belonging to the genus Fusarium. Indeed, over 5 billion dollars of crop loss have been attributed to FHB over the past decade. Shown here is the structure of trichothecene 3-O-acetyltransferase from F. graminearum complexed with deoxynivalenol superimposed onto an infected wheat head. This enzyme has promise for providing transgenic resistance to FHB.
Cell and Molecular Life Sciences: 2006
Title: Actin-Targeting Natural Products: Structures, Properties and Mechanisms of Action. Cell and Molecular Life Sciences, 63, 2119-2134.
Natural small-molecule inhibitors of actin cytoskeleton dynamics have long been recognized as valuable molecular probes for dissecting complex mechanisms of cellular function and have the potential to serve as chemotherapeutic drugs. This review focuses on the molecular and structural mechanism of actin-targeting natural products and provides a framework for the development of novel synthetic-compound designs with tailored functional properties that could be applied in both research and clinical settings. The cover shows the approximate binding sites of the filament-stabilizing natural products amphidinolide H, dolastatin 11, and phalloidin on F-actin.
Title: Three-dimensional Structure of the Tn5 Synaptic Complex Transposition Intermediate. Science, 289, 77-85.
Genomic evolution has been profoundly influenced by DNA transposition, a process whereby defined DNA segments move freely about the genome. Transposition is mediated by transposases, and similar events are catalyzed by retroviral integrases such as human immunodeficiency virus–1 (HIV-1) integrase. This cover depicts the structure of a bacterial transposase/DNA synaptic complex superimposed on Barbara McClintock’s original 1951 publication describing transposition in corn (reproduced with permission). The ends of the short DNA segments in the X-ray crystal structure have been extended to illustrate a complete transposable element. The structure provides a molecular framework for understanding many aspects of transposition, including the binding of transposon end DNA by one subunit and cleavage by a second, cleavage of two strands of DNA by a single active site via a hairpin intermediate, and strand transfer into target DNA.
Title: The structure of carbamoyl phosphate synthetase: A journey of 96 Å from substrate to product. Biochemistry, 36, 6305-6316
Carbamoyl phosphate synthetase is a multifunctional enzyme that catalyzes the production of carbamoyl phosphate from bicarbonate, glutamine, and two molecules of MgATP. The structural determination of this enzyme reveals that the enzyme consists of three active sites that lie along a 96 Å tunnel. This allows ammonia generated from glutamine in the first active site to travel to the second active site where it interacts with bicarbonate and ATP to yield carbamate which then diffuses to the third active site which uses another molecule of ATP to yield carbamoyl phosphate.
Title: Structural studies on myosin II: Communication between distant protein domains. Bioessays, 19, 561-569
Understanding how chemical energy is converted into directed movement is a fundamental problem in biology. In higher organisms this is accomplished primarily through the hydrolysis of ATP by three families of motors: myosin, dynein, and kinesin. The most abundant of these by mass is myosin, which operates against actin. This review summarizes the progress that has been made towards understanding the molecular basis of movement through the determination of the three-dimensional structures of myosin and actin.
Biophysical Society Discussions: 1994
Title: Structural studies of the myosin motor domain of Dictyostelium discoideum complexes: A revised model for the molecular basis of muscle contraction. (1995) Biophysical J., 68, 19s-28s
This study provided the first insight into the conformational changes in myosin that underlie the conversion of the chemical energy of hydrolysis of ATP into directed movement. This was accomplished by determining the structure of the Dictyostelium myosin II motor domain in the presence of ATP analogs that defined both the pre and post rigor states in the motile cycle.
Biochemistry Covers: 1995
The structural determination of myosin subfragment-1 (a proteolytic fragment of the entire myosin molecule that is sufficient to generate movement of actin in the presence of MgATP) was represented on the cover of Biochemistry for the first six months of 1995, even though there was no publication in that journal. Interestingly, the graphic artist incorporated the mirror image of the ribbon representation of myosin. As a consequence, for the first few months of 1995, Biochemistry portrayed a molecule with left-handed alpha helices. This was rectified, but months after the error was detected.
Myosin Subfragment-1: 1993
Titles: Three-dimensional structure of myosin subfragment-1: A molecular motor; (1993). Science, 261, 50-58; Structure of the actin-myosin complex and its implications for muscle contraction. (1993). Science, 261, 58-65
The determination of the structure of chicken skeletal myosin subfragment-1 and the generation of a model for the actomyosin complex in 1993 were landmarks in muscle and structural biology. The X-ray structure was the first structural determination of any molecular motor where it laid the foundation for a molecular hypothesis for muscle contraction. These papers were the results of ten years of effort following the initial crystallization of the myosin head.
Polyoma Virus: 1992
Title: Inside polyoma virus at 25-Å resolution. (1992). Nature, 355, 652-654
This study identified the location and arrangement of minor proteins in the capsid of polyoma virus and provided insight into the molecular arrangement of the viral mini-chromosome within the complete virion.
Title: Polyoma virus capsid structure at 22.5 Å resolution, (1982). Nature, 295, 110-115
This cover depicts the structure of polyoma virus at 22.5 Å resolution and demonstrates that its icosahedral capsid is assembled from 72 pentamers of the major coat protein rather than sixty hexamers and twelve pentamers as predicted by the principles of quasi-equivalence established by Caspar and Klug in 1962. This controversial study prompted a reexamination of quasiequivalence.