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1.
Hernia ; 17(1): 141-4, 2013 Feb.
Article in English | MEDLINE | ID: mdl-21584817

ABSTRACT

PURPOSE: Postoperative perineal hernias are rare complications from procedures, which compromise the pelvic floor, mainly abdominoperineal resection, proctocolectomy, and partial or total pelvic exenteration. Surgical repair can be accomplished through abdominal, laparoscopic, or transperineal approaches. METHODS: We present a case report of a 70-year-old man who underwent two prior operations for recurrent perineal hernia and was ultimately successfully treated with a third operation, a synthetic mesh redo procedure that utilized a synthetic mesh system marketed for women with pelvic organ prolapse. RESULTS: Although there is no "gold standard" for perineal hernia repair, our patient had multiple surgeries employing a variety of approaches. Final success was achieved using a mesh system with improved fixation to secure pelvic ligaments, using an exclusive perineal approach. Now, more than five years following the final surgery, the patient remains symptom free with no clinical evidence of perineal hernia recurrence. CONCLUSIONS: To date, this is the only report of using this mesh system in a male. The advantages of using this mesh system are (1) exclusive perineal approach without the accompanying risks of abdominal or laparoscopic approach; (2) improved fixation of mesh to secure pelvic ligaments; and (3) lightweight, flexible, and large mesh shape that can easily be trimmed to allow versatility in procedures.


Subject(s)
Hernia/diagnosis , Herniorrhaphy/methods , Perineum , Aged , Humans , Male , Recurrence , Reoperation , Surgical Mesh
2.
Tuberculosis (Edinb) ; 83(4): 223-49, 2003.
Article in English | MEDLINE | ID: mdl-12906835

ABSTRACT

The TB Structural Genomics Consortium is an organization devoted to encouraging, coordinating, and facilitating the determination and analysis of structures of proteins from Mycobacterium tuberculosis. The Consortium members hope to work together with other M. tuberculosis researchers to identify M. tuberculosis proteins for which structural information could provide important biological information, to analyze and interpret structures of M. tuberculosis proteins, and to work collaboratively to test ideas about M. tuberculosis protein function that are suggested by structure or related to structural information. This review describes the TB Structural Genomics Consortium and some of the proteins for which the Consortium is in the progress of determining three-dimensional structures.


Subject(s)
Genomics/organization & administration , Mycobacterium tuberculosis/genetics , Amino Acid Sequence , Bacterial Proteins/genetics , Genome, Bacterial , Humans , International Cooperation , Molecular Sequence Data , Mycobacterium tuberculosis/metabolism , Protein Conformation , Sequence Alignment
3.
Nat Struct Biol ; 8(9): 789-94, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11524683

ABSTRACT

Homologs of the Escherichia coli surE gene are present in many eubacteria and archaea. Despite the evolutionary conservation, little information is available on the structure and function of their gene products. We have determined the crystal structure of the SurE protein from Thermotoga maritima. The structure reveals the dimeric arrangement of the subunits and an active site around a bound metal ion. We also demonstrate that the SurE protein exhibits a divalent metal ion-dependent phosphatase activity that is inhibited by vanadate or tungstate. In the vanadate- and tungstate-complexed structures, the inhibitors bind adjacent to the divalent metal ion. Our structural and functional analyses identify the SurE proteins as a novel family of metal ion-dependent phosphatases.


Subject(s)
Acid Phosphatase , Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , Escherichia coli Proteins , Phosphoprotein Phosphatases/chemistry , Phosphoprotein Phosphatases/metabolism , Thermotoga maritima/enzymology , Amino Acid Sequence , Bacterial Proteins/antagonists & inhibitors , Bacterial Proteins/genetics , Binding Sites , Cations, Divalent/metabolism , Crystallography, X-Ray , Metals/metabolism , Models, Molecular , Molecular Sequence Data , Mutation/genetics , Phosphoprotein Phosphatases/antagonists & inhibitors , Phosphoprotein Phosphatases/genetics , Protein Structure, Secondary , Protein Structure, Tertiary , Sequence Alignment , Thermotoga maritima/genetics , Tungsten Compounds/metabolism , Tungsten Compounds/pharmacology , Vanadates/metabolism , Vanadates/pharmacology
4.
Nature ; 406(6796): 649-53, 2000 Aug 10.
Article in English | MEDLINE | ID: mdl-10949308

ABSTRACT

The transport of protons across membranes is an important process in cellular bioenergetics. The light-driven proton pump bacteriorhodopsin is the best-characterized protein providing this function. Photon energy is absorbed by the chromophore retinal, covalently bound to Lys 216 via a protonated Schiff base. The light-induced all-trans to 13-cis isomerization of the retinal results in deprotonation of the Schiff base followed by alterations in protonatable groups within bacteriorhodopsin. The changed force field induces changes, even in the tertiary structure, which are necessary for proton pumping. The recent report of a high-resolution X-ray crystal structure for the late M intermediate of a mutant bacteriorhopsin (with Asp 96-->Asn) displays the structure of a proton pathway highly disturbed by the mutation. To observe an unperturbed proton pathway, we determined the structure of the late M intermediate of wild-type bacteriorhodopsin (2.25 A resolution). The cytoplasmic side of our M2 structure shows a water net that allows proton transfer from the proton donor group Asp 96 towards the Schiff base. An enlarged cavity system above Asp 96 is observed, which facilitates the de- and reprotonation of this group by fluctuating water molecules in the last part of the cycle.


Subject(s)
Bacteriorhodopsins/chemistry , Proton Pumps/chemistry , Bacteriorhodopsins/genetics , Bacteriorhodopsins/metabolism , Biological Transport , Crystallography, X-Ray , Cytoplasm/metabolism , Models, Molecular , Point Mutation , Protein Conformation , Protein Structure, Tertiary , Proton Pumps/metabolism , Protons
5.
Science ; 287(5458): 1615-22, 2000 Mar 03.
Article in English | MEDLINE | ID: mdl-10698731

ABSTRACT

Members of the cytochrome P450 superfamily catalyze the addition of molecular oxygen to nonactivated hydrocarbons at physiological temperature-a reaction that requires high temperature to proceed in the absence of a catalyst. Structures were obtained for three intermediates in the hydroxylation reaction of camphor by P450cam with trapping techniques and cryocrystallography. The structure of the ferrous dioxygen adduct of P450cam was determined with 0.91 angstrom wavelength x-rays; irradiation with 1.5 angstrom x-rays results in breakdown of the dioxygen molecule to an intermediate that would be consistent with an oxyferryl species. The structures show conformational changes in several important residues and reveal a network of bound water molecules that may provide the protons needed for the reaction.


Subject(s)
Camphor 5-Monooxygenase/chemistry , Camphor 5-Monooxygenase/metabolism , Camphor/chemistry , Camphor/metabolism , Catalysis , Crystallization , Crystallography, X-Ray , Electrons , Ferric Compounds/chemistry , Ferric Compounds/metabolism , Ferrous Compounds/chemistry , Ferrous Compounds/metabolism , Hydrogen Bonding , Hydroxylation , Ligands , Models, Molecular , Molecular Conformation , Oxygen/chemistry , Oxygen/metabolism , Protein Conformation , Protein Structure, Secondary , Protons , Pseudomonas putida/enzymology , Water/chemistry , Water/metabolism
6.
Nature ; 403(6772): 921-3, 2000 Feb 24.
Article in English | MEDLINE | ID: mdl-10706294

ABSTRACT

Small molecules such as NO, O2, CO or H2 are important biological ligands that bind to metalloproteins to function crucially in processes such as signal transduction, respiration and catalysis. A key issue for understanding the regulation of reaction mechanisms in these systems is whether ligands gain access to the binding sites through specific channels and docking sites, or by random diffusion through the protein matrix. A model system for studying this issue is myoglobin, a simple haem protein. Myoglobin has been studied extensively by spectroscopy, crystallography, computation and theory. It serves as an aid to oxygen diffusion but also binds carbon monoxide, a byproduct of endogenous haem catabolism. Molecular dynamics simulations, random mutagenesis and flash photolysis studies indicate that ligand migration occurs through a limited number of pathways involving docking sites. Here we report the 1.4 A resolution crystal structure of a ligand-binding intermediate in carbonmonoxy myoglobin that may have far-reaching implications for understanding the dynamics of ligand binding and catalysis.


Subject(s)
Myoglobin/chemistry , Animals , Binding Sites , Carbon Monoxide/chemistry , Carbon Monoxide/metabolism , Crystallography, X-Ray , Horses , Ligands , Myoglobin/metabolism , Oxygen/chemistry , Oxygen/metabolism , Protein Conformation
7.
Proc Natl Acad Sci U S A ; 97(5): 2058-63, 2000 Feb 29.
Article in English | MEDLINE | ID: mdl-10681426

ABSTRACT

We determined the structure of the photolytic intermediate of a sperm whale myoglobin (Mb) mutant called Mb-YQR [Leu-(B10)-->Tyr; His(E7)-->Gln; Thr(E10)-->Arg] to 1.4-A resolution by ultra-low temperature (20 K) x-ray diffraction. Starting with the CO complex, illumination leads to photolysis of the Fe-CO bond, and migration of the photolyzed carbon monoxide (CO*) to a niche in the protein 8.1 A from the heme iron; this cavity corresponds to that hosting an atom of Xe when the crystal is equilibrated with xenon gas at 7 atmospheres [Tilton, R. F., Jr., Kuntz, I. D. & Petsko, G. A. (1984) Biochemistry 23, 2849-2857]. The site occupied by CO* corresponds to that predicted by molecular dynamics simulations previously carried out to account for the NO geminate rebinding of Mb-YQR observed in laser photolysis experiments at room temperature. This secondary docking site differs from the primary docking site identified by previous crystallographic studies on the photolyzed intermediate of wild-type sperm whale Mb performed at cryogenic temperatures [Teng et al. (1994) Nat. Struct. Biol. 1, 701-705] and room temperature [Srajer et al. (1996) Science 274, 1726-1729]. Our experiment shows that the pathway of a small molecule in its trajectory through a protein may be modified by site-directed mutagenesis, and that migration within the protein matrix to the active site involves a limited number of pre-existing cavities identified in the interior space of the protein.


Subject(s)
Myoglobin/chemistry , Amino Acid Sequence , Animals , Crystallography, X-Ray , Ligands , Molecular Sequence Data , Mutagenesis , Myoglobin/genetics , Myoglobin/metabolism , Photolysis , Protein Conformation , Whales
8.
Biophys J ; 77(4): 2153-74, 1999 Oct.
Article in English | MEDLINE | ID: mdl-10512835

ABSTRACT

We have used x-ray crystallography to determine the structures of sperm whale myoglobin (Mb) in four different ligation states (unligated, ferric aquomet, oxygenated, and carbonmonoxygenated) to a resolution of better than 1.2 A. Data collection and analysis were performed in as much the same way as possible to reduce model bias in differences between structures. The structural differences among the ligation states are much smaller than previously estimated, with differences of <0.25 A root-mean-square deviation among all atoms. One structural parameter previously thought to vary among the ligation states, the proximal histidine (His-93) azimuthal angle, is nearly identical in all the ferrous complexes, although the tilt of the proximal histidine is different in the unligated form. There are significant differences, however, in the heme geometry, in the position of the heme in the pocket, and in the distal histidine (His-64) conformations. In the CO complex the majority conformation of ligand is at an angle of 18 +/- 3 degrees with respect to the heme plane, with a geometry similar to that seen in encumbered model compounds; this angle is significantly smaller than reported previously by crystallographic studies on monoclinic Mb crystals, but still significantly larger than observed by photoselection. The distal histidine in unligated Mb and in the dioxygenated complex is best described as having two conformations. Two similar conformations are observed in MbCO, in addition to another conformation that has been seen previously in low-pH structures where His-64 is doubly protonated. We suggest that these conformations of the distal histidine correspond to the different conformational substates of MbCO and MbO(2) seen in vibrational spectra. Full-matrix refinement provides uncertainty estimates of important structural parameters. Anisotropic refinement yields information about correlated disorder of atoms; we find that the proximal (F) helix and heme move approximately as rigid bodies, but that the distal (E) helix does not.


Subject(s)
Carbon Monoxide/metabolism , Metmyoglobin/chemistry , Myoglobin/chemistry , Oxygen/metabolism , Animals , Anisotropy , Binding Sites , Crystallization , Crystallography, X-Ray/instrumentation , Crystallography, X-Ray/methods , Electrons , Heme/chemistry , Heme/metabolism , Histidine/chemistry , Histidine/metabolism , Hydrogen Bonding , Ligands , Metmyoglobin/metabolism , Models, Molecular , Myoglobin/metabolism , Protein Conformation , Protons , Water/chemistry , Water/metabolism , Whales
9.
Acta Crystallogr D Biol Crystallogr ; 55(Pt 11): 1872-7, 1999 Nov.
Article in English | MEDLINE | ID: mdl-10531485

ABSTRACT

It has recently been shown that the standard deviation of local r.m. s. electron density is a good indicator of the presence of distinct regions of solvent and protein in macromolecular electron-density maps [Terwilliger & Berendzen (1999). Acta Cryst. D55, 501-505]. Here, it is demonstrated that a complementary measure, the correlation of local r.m.s. density in adjacent regions on the unit cell, is also a good measure of the presence of distinct solvent and protein regions. The correlation of local r.m.s. density is essentially a measure of how contiguous the solvent (and protein) regions are in the electron-density map. This statistic can be calculated in real space or in reciprocal space and has potential uses in evaluation of heavy-atom solutions in the MIR and MAD methods as well as for evaluation of trial phase sets in ab initio phasing procedures.


Subject(s)
Crystallography, X-Ray/methods , Proteins/chemistry , Bacterial Proteins/chemistry , Computer Simulation , Macromolecular Substances , Rhodococcus , Software , Solvents/chemistry
10.
Nat Biotechnol ; 17(7): 691-5, 1999 Jul.
Article in English | MEDLINE | ID: mdl-10404163

ABSTRACT

Formation of the chromophore of green fluorescent protein (GFP) depends on the correct folding of the protein. We constructed a "folding reporter" vector, in which a test protein is expressed as an N-terminal fusion with GFP. Using a test panel of 20 proteins, we demonstrated that the fluorescence of Escherichia coli cells expressing such GFP fusions is related to the productive folding of the upstream protein domains expressed alone. We used this fluorescent indicator of protein folding to evolve proteins that are normally prone to aggregation during expression in E. coli into closely related proteins that fold robustly and are fully soluble and functional. This approach to improving protein folding does not require functional assays for the protein of interest and provides a simple route to improving protein folding and expression by directed evolution.


Subject(s)
Escherichia coli/metabolism , Luminescent Proteins , Protein Folding , Archaeal Proteins/chemistry , Archaeal Proteins/genetics , Archaeal Proteins/metabolism , Directed Molecular Evolution , Escherichia coli/genetics , Ferritins/chemistry , Ferritins/genetics , Ferritins/metabolism , Fluorescence , Green Fluorescent Proteins , Inclusion Bodies , Luminescent Proteins/chemistry , Luminescent Proteins/genetics , Luminescent Proteins/metabolism , Point Mutation , Protein Biosynthesis , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/metabolism , Solubility , Temperature , Transcription, Genetic
11.
Acta Crystallogr D Biol Crystallogr ; 55(Pt 4): 849-61, 1999 Apr.
Article in English | MEDLINE | ID: mdl-10089316

ABSTRACT

Obtaining an electron-density map from X-ray diffraction data can be difficult and time-consuming even after the data have been collected, largely because MIR and MAD structure determinations currently require many subjective evaluations of the qualities of trial heavy-atom partial structures before a correct heavy-atom solution is obtained. A set of criteria for evaluating the quality of heavy-atom partial solutions in macromolecular crystallography have been developed. These have allowed the conversion of the crystal structure-solution process into an optimization problem and have allowed its automation. The SOLVE software has been used to solve MAD data sets with as many as 52 selenium sites in the asymmetric unit. The automated structure-solution process developed is a major step towards the fully automated structure-determination, model-building and refinement procedure which is needed for genomic scale structure determinations.


Subject(s)
Crystallography, X-Ray/methods , Algorithms , Data Interpretation, Statistical , Fourier Analysis , Molecular Structure , Scattering, Radiation , Software , Solutions , X-Rays
12.
Acta Crystallogr D Biol Crystallogr ; 55(Pt 2): 501-5, 1999 Feb.
Article in English | MEDLINE | ID: mdl-10089362

ABSTRACT

An automated examination of the native Fourier is tested as a means of evaluation of a heavy-atom solution in MAD and MIR methods for macromolecular crystallography. It is found that the presence of distinct regions of high and low density variation in electron-density maps is a good indicator of the correctness of a heavy-atom solution in the MIR and MAD methods. The method can be used to evaluate heavy-atom solutions during MAD and MIR structure solutions and to determine the handedness of the structure if anomalous data have been measured.


Subject(s)
Fourier Analysis , Proteins/chemistry , Solvents/chemistry , Evaluation Studies as Topic , Methods , Solutions/chemistry
13.
Genetica ; 106(1-2): 141-7, 1999.
Article in English | MEDLINE | ID: mdl-10710720

ABSTRACT

The genome projects are changing biology by providing the genetic blueprints of entire organisms. The blueprints are tantalizing but we cannot deduce everything we need to know from them, including the structures and detailed functions of proteins. In this paper we describe an approach for obtaining structural information about proteins on a genomic scale. We describe how structural and functional information might eventually be put together to form a basis for describing life at many levels. We then describe how structural information fits into this picture and classes of proteins for which structural information would be useful in a genomic context. We conclude with a proposal for an initiative to determine protein structures on a very large scale.


Subject(s)
Proteins/chemistry , Amino Acid Motifs , Bacterial Proteins/chemistry , Databases, Factual , Escherichia coli/chemistry , Female , Humans , Plant Proteins/chemistry , Protein Structure, Tertiary , Rhodobacter/chemistry , Xanthobacter/chemistry
14.
Protein Sci ; 7(9): 1851-6, 1998 Sep.
Article in English | MEDLINE | ID: mdl-9761466

ABSTRACT

The recent sequencing of many complete genomes, combined with the development of methods that allow rapid structure determination for many proteins, has changed the way in which protein structure determinations can be approached. One-by-one determinations of individual protein structures will soon be augmented by class-directed structure analyses in which a group of proteins is targeted and structures of representative members are determined and used to represent the entire group. Such a shift in approach would be the foundation for a broad protein structure initiative targeting classes of proteins important for biotechnology and for a fundamental understanding of protein function.


Subject(s)
Epitopes/chemistry , Immunoglobulin Fab Fragments/chemistry , Muramidase/chemistry , Animals , Antigen-Antibody Complex/chemistry , Chickens , Kinetics , Models, Molecular , Muramidase/genetics , Mutation/genetics
15.
Structure ; 6(9): 1207-14, 1998 Sep 15.
Article in English | MEDLINE | ID: mdl-9753699

ABSTRACT

BACKGROUND: Translation initiation factor 5A (IF-5A) is reported to be involved in the first step of peptide bond formation in translation, to be involved in cell-cycle regulation and to be a cofactor for the Rev and Rex transactivator proteins of human immunodeficiency virus-1 and T-cell leukemia virus I, respectively. IF-5A contains an unusual amino acid, hypusine (N-epsilon-(4-aminobutyl-2-hydroxy)lysine), that is required for its function. The first step in the post-translational modification of lysine to hypusine is catalyzed by the enzyme deoxyhypusine synthase, the structure of which has been published recently. RESULTS: IF-5A from the archebacterium Pyrobaculum aerophilum has been heterologously expressed in Escherichia coli with selenomethionine substitution. The crystal structure of IF-5A has been determined by multiwavelength anomalous diffraction and refined to 1.75 A. Unmodified P. aerophilum IF-5A is found to be a beta structure with two domains and three separate hydrophobic cores. CONCLUSIONS: The lysine (Lys42) that is post-translationally modified by deoxyhypusine synthase is found at one end of the IF-5A molecule in an turn between beta strands beta4 and beta5; this lysine residue is freely solvent accessible. The C-terminal domain is found to be homologous to the cold-shock protein CspA of E. coli, which has a well characterized RNA-binding fold, suggesting that IF-5A is involved in RNA binding.


Subject(s)
Peptide Initiation Factors/chemistry , Peptide Initiation Factors/ultrastructure , RNA-Binding Proteins , Thermoproteaceae/chemistry , Amino Acid Sequence , Cloning, Molecular , Crystallography, X-Ray , DNA, Archaeal/chemistry , Escherichia coli , Humans , Models, Molecular , Molecular Sequence Data , Open Reading Frames , Peptide Initiation Factors/genetics , Protein Conformation , Protein Folding , Protein Structure, Secondary , Sequence Alignment , Static Electricity , Thermoproteaceae/genetics , Eukaryotic Translation Initiation Factor 5A
16.
Structure ; 5(6): 735-9, 1997 Jun 15.
Article in English | MEDLINE | ID: mdl-9261074

ABSTRACT

A first real glance at the structural, spectral and temporal interplay that constitutes the photocycle of the photoactive yellow protein (PYP) has been obtained from a combination of time-resolved crystallography with mutational analysis and spectroscopic studies.


Subject(s)
Bacterial Proteins/chemistry , Bacterial Proteins/physiology , Photoreceptors, Microbial , Binding Sites , Crystallography, X-Ray , Models, Molecular , Mutation , Protein Conformation , Spectrum Analysis
17.
Acta Crystallogr D Biol Crystallogr ; 53(Pt 5): 571-9, 1997 Sep 01.
Article in English | MEDLINE | ID: mdl-15299888

ABSTRACT

A Bayesian treatment for phase calculation in the multiwavelength anomalous diffraction (MAD) technique is presented. This approach explicitly treats effects of errors correlated among measurements at different wavelengths and between Bijvoet pairs. The resulting method, which is called Bayesian correlated MAD phasing, gives proper statistical consideration to all data and does not give special treatment to data from a particular wavelength. Results obtained using Bayesian correlated MAD phasing and two other strategies on both a model test case and on data obtained in two actual MAD experiments are compared. Although all procedures performed well when the completeness of the data was high, it is shown that Bayesian correlated MAD phasing is more robust with respect to incompleteness of data than the other methods are. At 60% completeness the improvement over other methods for the examples given was nearly 50% in the correlation coefficients, and made a substantial difference in the interpretability of an electron-density map.

18.
Acta Crystallogr D Biol Crystallogr ; 52(Pt 5): 1004-11, 1996 Sep 01.
Article in English | MEDLINE | ID: mdl-15299610

ABSTRACT

Interest in a pair of highly isomorphous structures often focuses on the differences between them. In cases where substantial correlated model errors exist or where there are differences in the quality of the two experimental data sets (cases quite common in macromolecular crystallography), independent refinement of the two structures does not lead to the most accurate estimate of the differences between them. An alternative procedure that has proven effective in some such cases is difference refinement, in which the residual between observed and calculated differences in structure-factor amplitudes between the two structures is minimized. A Bayesian approach has been used to extend the range of applicability of difference refinement to cases where there is only partial correlation in model errors and where the overlap between the data sets is limited. The resulting method, Bayesian difference refinement, uses residuals to be minimized that vary smoothly between difference refinement and independent refinement. When the errors in the two structural models are very similar, difference refinement is used; when they are very different, independent refinement is used; and when they are partially correlated, a combination of the two is used. The procedure is very simple to apply and does not significantly increase the computational demands of refinement.

19.
Acta Crystallogr D Biol Crystallogr ; 52(Pt 4): 743-8, 1996 Jul 01.
Article in English | MEDLINE | ID: mdl-15299638

ABSTRACT

A simple weighting scheme for atomic refinement is discussed. The approach, called 'Bayesian weighting', is designed to be robust with respect to the bias that arises from the incomplete nature of the atomic model, which in macromolecular crystallography is typically quite serious. Bayesian weights are based on the mean-squared residual errors over shells of resolution, with centric and acentric reflections considered separately and with allowances made for experimental uncertainties. Use of Bayesian weighting is shown in test cases typical for macromolecular crystallography to improve the accuracy of the refined coordinates when compared with schemes employing unit weights or experimental variances.

20.
Acta Crystallogr D Biol Crystallogr ; 52(Pt 4): 749-57, 1996 Jul 01.
Article in English | MEDLINE | ID: mdl-15299639

ABSTRACT

Substantial highly correlated differences sometimes exist between a series of heavy-atom derivatives of a macromolecule and the native structure. Use of such a series of derivatives for phase determination by multiple isomorphous replacement (MIR) has been difficult because MIR analysis has treated errors as independent. A simple Bayesian approach has been used to derive probability distributions for the phase in the case where a group of MIR derivatives have correlated errors. The utility of the resulting 'correlated-phasing' method has been examined by applying it to both simulated and real MIR data sets that contain sizeable correlated errors and it has been found that it can dramatically improve MIR phase estimates in these cases. Correlated phasing is applicable to situations where derivatives exhibit substantial correlated changes in protein conformation or crystal packing or where correlated errors in heavy-atom models are large. Correlated phasing does not substantially increase the complexity of phase computation and is suitable for routine use.

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