Macromolecular Crystallographic Computing

Author(s):  
Kostas Bethanis ◽  
Petros Giastas ◽  
Trias Thireou ◽  
Vassilis Atlamazoglou

Structural genomics or structural proteomics can be defined as the quest to obtain the three-dimensional structures of all proteins. Single-crystal X-ray crystallography provides the most direct, accurate and in most of the cases the only way of forming images of macromolecules. Using crystallography, threedimensional images have been made of thousands of macromolecules, especially proteins and nucleic acids. These give detailed information about their activity, their mechanism for recognizing and binding substrates and effectors, and the conformational changes which they may undergo. This chapter presents the basic crystallographic procedure steps and a thorough survey of the computational software used most frequently by protein X-ray crystallographers. The determination of the structure of 2[4Fe-4S] ferredoxin from Escherichia coli. is examined as a case study of implementation of these steps and programs. Finally, some of the perspectives of the field of computational X-ray crystallography are noted showing the future developments in the ceaseless evolution of new methods and proliferation of new programs.

2018 ◽  
Vol 19 (11) ◽  
pp. 3401 ◽  
Author(s):  
Ashutosh Srivastava ◽  
Tetsuro Nagai ◽  
Arpita Srivastava ◽  
Osamu Miyashita ◽  
Florence Tama

Protein structural biology came a long way since the determination of the first three-dimensional structure of myoglobin about six decades ago. Across this period, X-ray crystallography was the most important experimental method for gaining atomic-resolution insight into protein structures. However, as the role of dynamics gained importance in the function of proteins, the limitations of X-ray crystallography in not being able to capture dynamics came to the forefront. Computational methods proved to be immensely successful in understanding protein dynamics in solution, and they continue to improve in terms of both the scale and the types of systems that can be studied. In this review, we briefly discuss the limitations of X-ray crystallography in studying protein dynamics, and then provide an overview of different computational methods that are instrumental in understanding the dynamics of proteins and biomacromolecular complexes.


2016 ◽  
Vol 12 ◽  
pp. 2828-2833 ◽  
Author(s):  
Roman Sommer ◽  
Dirk Hauck ◽  
Annabelle Varrot ◽  
Anne Imberty ◽  
Markus Künzler ◽  
...  

Selenoglycosides are used as reactive glycosyl donors in the syntheses of oligosaccharides. In addition, such heavy atom analogs of natural glycosides are useful tools for structure determination of their lectin receptors using X-ray crystallography. Some lectins, e.g., members of the tectonin family, only bind to carbohydrate epitopes with O-alkylated ring hydroxy groups. In this context, we report the first synthesis of an O-methylated selenoglycoside, specifically methyl 2-O-methyl-L-selenofucopyranoside, a ligand of the lectin tectonin-2 from the mushroom Laccaria bicolor. The synthetic route required a strategic revision and further optimization due to the intrinsic lability of alkyl selenoglycosides, in particular for the labile fucose. Here, we describe a successful synthetic access to methyl 2-O-methyl-L-selenofucopyranoside in 9 linear steps and 26% overall yield starting from allyl L-fucopyranoside.


2007 ◽  
Vol 362 (1482) ◽  
pp. 1035-1042 ◽  
Author(s):  
Zihe Rao

China has a strong background in X-ray crystallography dating back to the 1920s. Protein crystallography research in China was first developed following the successful synthesis of insulin in China in 1966. The subsequent determination of the three-dimensional structure of porcine insulin made China one of the few countries which could determine macromolecular structures by X-ray diffraction methods in the late 1960s and early 1970s. After a slow period during the 1970s and 1980s, protein crystallography in China has reached a new climax with a number of outstanding accomplishments. Here, I review the history and progress of protein crystallography in China and detail some of the recent research highlights, including the crystal structures of two membrane proteins as well as the structural genomics initiative in China.


2020 ◽  
Vol 48 (6) ◽  
pp. 2505-2524
Author(s):  
Tristan O. C. Kwan ◽  
Danny Axford ◽  
Isabel Moraes

The aim of structural biology has been always the study of biological macromolecules structures and their mechanistic behaviour at molecular level. To achieve its goal, multiple biophysical methods and approaches have become part of the structural biology toolbox. Considered as one of the pillars of structural biology, X-ray crystallography has been the most successful method for solving three-dimensional protein structures at atomic level to date. It is however limited by the success in obtaining well-ordered protein crystals that diffract at high resolution. This is especially true for challenging targets such as membrane proteins (MPs). Understanding structure-function relationships of MPs at the biochemical level is vital for medicine and drug discovery as they play critical roles in many cellular processes. Though difficult, structure determination of MPs by X-ray crystallography has significantly improved in the last two decades, mainly due to many relevant technological and methodological developments. Today, numerous MP crystal structures have been solved, revealing many of their mechanisms of action. Yet the field of structural biology has also been through significant technological breakthroughs in recent years, particularly in the fields of single particle electron microscopy (cryo-EM) and X-ray free electron lasers (XFELs). Here we summarise the most important advancements in the field of MP crystallography and the significance of these developments in the present era of modern structural biology.


2011 ◽  
Vol 17 (6) ◽  
pp. 879-885 ◽  
Author(s):  
Linhua Jiang ◽  
Dilyana Georgieva ◽  
Igor Nederlof ◽  
Zunfeng Liu ◽  
Jan Pieter Abrahams

AbstractThree-dimensional nanocrystals can be studied by electron diffraction using transmission cryo-electron microscopy. For molecular structure determination of proteins, such nanosized crystalline samples are out of reach for traditional single-crystal X-ray crystallography. For the study of materials that are not sensitive to the electron beam, software has been developed for determining the crystal lattice and orientation parameters. These methods require radiation-hard materials that survive careful orienting of the crystals and measuring diffraction of one and the same crystal from different, but known directions. However, as such methods can only deal with well-oriented crystalline samples, a problem exists for three-dimensional (3D) crystals of proteins and other radiation sensitive materials that do not survive careful rotational alignment in the electron microscope. Here, we discuss our newly released software AMP that can deal with nonoriented diffraction patterns, and we discuss the progress of our new preprocessing program that uses autocorrelation patterns of diffraction images for lattice determination and indexing of 3D nanocrystals.


2015 ◽  
Vol 71 (10) ◽  
pp. 1205-1214 ◽  
Author(s):  
Lauren Sartor ◽  
Charmaine Ibarra ◽  
Ahmad Al-Mestarihi ◽  
Brian O. Bachmann ◽  
Jessica L. Vey

The anthracyclines are a class of highly effective natural product chemotherapeutics and are used to treat a range of cancers, including leukemia. The toxicity of the anthracyclines has stimulated efforts to further diversify the scaffold of the natural product, which has led to renewed interest in the biosynthetic pathway responsible for the formation and modification of this family of molecules. DnmZ is an N-hydroxylating flavin monooxygenase (a nitrososynthase) that catalyzes the oxidation of the exocyclic amine of the sugar nucleotide dTDP-L-epi-vancosamine to its nitroso form. Its specific role in the anthracycline biosynthetic pathway involves the synthesis of the seven-carbon acetal moiety attached to C4 of L-daunosamine observed in the anthracycline baumycin. Here, X-ray crystallography was used to elucidate the three-dimensional structure of DnmZ. Two crystal structures of DnmZ were yielded: that of the enzyme alone, solved to 3.00 Å resolution, and that of the enzyme in complex with thymidine diphosphate, the nucleotide carrier portion of the substrate, solved to 2.74 Å resolution. These models add insights into the structural features involved in substrate specificity and conformational changes involved in thymidine diphosphate binding by the nitrososynthases.


Author(s):  
Qingqiu Huang ◽  
Doletha M. E. Szebenyi

The production of high-quality crystals is one of the major obstacles in determining the three-dimensional structure of macromolecules by X-ray crystallography. It is fairly common that a visually well formed crystal diffracts poorly to a resolution that is too low to be suitable for structure determination. Dehydration has proven to be an effective post-crystallization treatment for improving crystal diffraction quality. Several dehydration methods have been developed, but no single one of them is suitable for all crystals. Here, a new convenient and effective dehydration method is reported that makes use of a dehydrating solution that will not dry out in air for several hours. Using this dehydration method, the resolution ofArchaeoglobus fulgidusCas5a crystals has been increased from 3.2 to 1.95 Å and the resolution ofEscherichia coliLptA crystals has been increased from <5 to 3.4 Å.


1999 ◽  
Vol 10 (6) ◽  
pp. 2063-2074 ◽  
Author(s):  
Keiko Hirose ◽  
Jan Löwe ◽  
Maria Alonso ◽  
Robert A. Cross ◽  
Linda A. Amos

We present a new map showing dimeric kinesin bound to microtubules in the presence of ADP that was obtained by electron cryomicroscopy and image reconstruction. The directly bound monomer (first head) shows a different conformation from one in the more tightly bound empty state. This change in the first head is amplified as a movement of the second (tethered) head, which tilts upward. The atomic coordinates of kinesin·ADP dock into our map so that the tethered head associates with the bound head as in the kinesin dimer structure seen by x-ray crystallography. The new docking orientation avoids problems associated with previous predictions; it puts residues implicated by proteolysis-protection and mutagenesis studies near the microtubule but does not lead to steric interference between the coiled-coil tail and the microtubule surface. The observed conformational changes in the tightly bound states would probably bring some important residues closer to tubulin. As expected from the homology with kinesin, the atomic coordinates of nonclaret disjunctional protein (ncd)·ADP dock in the same orientation into the attached head in a map of microtubules decorated with dimeric ncd·ADP. Our results support the idea that the observed direct interaction between the two heads is important at some stages of the mechanism by which kinesin moves processively along microtubules.


Author(s):  
S. Cusack ◽  
J.-C. Jésior

Three-dimensional reconstruction techniques using electron microscopy have been principally developed for application to 2-D arrays (i.e. monolayers) of biological molecules and symmetrical single particles (e.g. helical viruses). However many biological molecules that crystallise form multilayered microcrystals which are unsuitable for study by either the standard methods of 3-D reconstruction or, because of their size, by X-ray crystallography. The grid sectioning technique enables a number of different projections of such microcrystals to be obtained in well defined directions (e.g. parallel to crystal axes) and poses the problem of how best these projections can be used to reconstruct the packing and shape of the molecules forming the microcrystal.Given sufficient projections there may be enough information to do a crystallographic reconstruction in Fourier space. We however have considered the situation where only a limited number of projections are available, as for example in the case of catalase platelets where three orthogonal and two diagonal projections have been obtained (Fig. 1).


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