The G473D mutation impairs dimerization and catalysis in human sulfite oxidase

Among the mutations identified in patients with isolated sulfite oxidase deficiency, the G473D variant is of particular interest since sedimentation analysis reveals that this variant is a monomer, and the importance of the wild-type dimeric state of mammalian sulfite oxidase is not yet well understood. Analysis of recombinant G473D sulfite oxidase indicated that it is severely impaired both in the ability to bind sulfite and in catalysis, with a second-order rate constant 5 orders of magnitude lower than that of the wild type. To elucidate the specific reasons for the severe effects seen in the G473D variant, several other variants were created, including G473A, G473W, and the double mutant R212A/G473D. Despite the inability to form a stable dimer, the G473W variant had 5-fold higher activity than G473D and nearly wild-type activity at pH 7.0 when ferricyanide was the electron acceptor. In contrast, the R212A/G473D variant demonstrated some ability to oligomerize but had undetectable activity. The G473A variant retained the ability to dimerize and had steady-state activity that was comparable to that of the wild type. Furthermore, stopped-flow analysis of the reductive half-reaction of this variant yielded a rate constant nearly 3 times higher than that of the wild type. Examination of the secondary structures of the variants by CD spectroscopy indicated significant random-coil formation in G473D, G473W, and R212A/G473D. These results demonstrate that both the charge and the large size of an Asp residue in this position contribute to the severe effects seen in a patient with the G473D mutation, by causing partial misfolding and monomerization of sulfite oxidase and attenuating both substrate binding and catalytic efficiency during the reaction cycle.     

Forensic dentistry joins DNA analysis as important tool for police work.

A Vancouver dentist who works as a teacher, researcher and administrator at the University of British Columbia has a unique extracurricular interest. Dr. David Sweet, one of four forensic odontologists in Canada, has put names to unidentified bodies and the remains of car-crash victims, helped convict child abusers and provided evidence in robbery cases.     

Lysyl oxidase G473A polymorphism is associated with increased risk of coronary artery diseases

Lysyl oxidase (LOX) plays a crucial role in the maintenance of extracellular matrix stability and could participate in vascular remodeling associated with cardiovascular diseases. A novel polymorphism in the LOX gene, G473A (rs1800449), was identified. The objective of this study was to investigate the association between LOX G473A polymorphism and susceptibility to coronary artery diseases (CADs) in Chinese population. The LOX variant G473A was detected by polymerase chain reaction-restriction fragment length polymorphism in 656 CAD cases and 718 age-matched controls. Frequencies of LOX 473 AA genotype and A allele were significantly higher in patients with CAD than in controls (odds ratio?=?1.93, 95% confidence interval 1.26-2.95, p?=?0.002; and odds ratio?=?1.38, 95% confidence interval 1.15-1.67, p?=?0.001). Our data suggest that the G473A polymorphism of LOX gene is associated with increased susceptibility to CAD.     

The pathogenic human sulfite oxidase mutants G473D and A208D are defective in intramolecular electron transfer

Mutations G473D and A208D were identified in patients with isolated sulfite oxidase (SO) deficiency, and the equivalent amino acids (G451 and A186, respectively) have been localized to the vicinity of the molybdopterin active site in the X-ray structure of chicken SO [Kisker, C., Schindelin, H., Pacheco, A., Wehbi, W., Garrett, R. M., Rajagopalan, K. V., Enemark, J. H., and Rees, D. C. (1997) Cell 91, 973-983]. To assess the effects of these mutations in human SO, steady-state kinetic studies of enzyme turnover and laser flash photolysis measurements of intramolecular electron transfer (IET) rate constants between the reduced heme [Fe(II)] and Mo(VI) centers were carried out in the recombinant G473D, G473A, G473W, G473D/R212A, and A208D human SO mutants. In the G473D and A208D mutants, the IET rate constants at pH 6.0 are decreased by 3 orders of magnitude relative to that of the wild type. Steady-state kinetic measurements indicate that the IET process is the rate-limiting step in the catalytic cycle of these two mutants. Thus, the large decreases in the IET rate constants and the kcat values, and the large increases in the Km(sulfite) values, rationalize the fatal impact of these mutations. Far-UV CD spectra of G473D indicate that the protein backbone conformation is remarkably changed, and the sedimentation equilibrium indicates that the protein is monomeric. Furthermore, EPR studies also suggest that the active site structure of the Mo(V) form of A208D is different from that of the wild type. In contrast, similar studies on G473A show that it is dimeric, that its Mo(V) active site structure is similar to that of the wild type, and that its IET rate constant is only 2.6-fold smaller than that of the wild type. IET in G473W is severely impaired, and no IET is observed for G473D/R212A. In chicken SO, the equivalent residues (G451 and A186) are both buried inside the protein. Thus, for human SO, the mutations to charged residues at the equivalent sites most likely cause crucial global or localized structural changes, and expose an alternative docking site that may compete with the Mo domain for docking of the heme, thereby retarding IET and efficient catalytic turnover of the sulfite oxidation reaction.     

Deportation proceedings against Canadian MDs may hold lesson for others heading south

Two Alberta physicians who emigrated to a medically underserviced part of Kentucky have learned a harsh lesson about American immigration law. Drs. David Zetter and Sabina Seitz had been settled in western Kentucky for 2 years when the US government launched deportation proceedings against them. American officials allege that they misrepresented themselves when they entered the US on a temporary visa. They may be allowed to stay following a public outcry against their deportation.     

中国药用真菌名录及部分名称的修订

近年来,我国对药用真菌的研究和利用越来越重视,相关报道逐年增加。针对有些种类鉴定有误、拉丁学名使用没有严格遵守最新国际植物命名法规、命名人缩写不规范等问题,作者系统考证了我国药用真菌的名称,共收录473种,对每种名称按新近的研究成果和最新命名法规(维也纳法规)进行了订正,对过去的错误报道或不存在的名称进行了修正,将曾报道的、但应作为其他种的同物异名者列在其正名之后,所有名称定名人的缩写全部按国际植物命名法规的要求加以规范化。每种名称之后还列举了该种的主要药用功能或价值,并引证了主要参考文献。     

Typification of the Boissier names in Anthriscus Pers. (Apiaceae)

Boissier described several taxa in Anthriscus , summarized in his Flora orientalis account. The names include A. lamprocarpa, A. kotschyi, A. ruprechtii, A. tenerrima, A. t. var. leiocarpa, A. anatolica, A. macrocarpa, A. nemorosa var. mollis, A. n. var. glabra; the hst four are still recognized as separate species. These names are typified in this paper, based on the material in Boissier herbarium at G.     

Book Reviews

Book reviewed in this article:
GENERAL AND ETHNOLOGY: The Teaching of Anthropology. David G. Mandelbaum, Gabriel W. Lasker, and Ethel M. Albert
GENERAL AND ETHNOLOGY: Resources for the Teaching of Anthropology. David G. Mandelbaum, Gabriel W. Lasker, and Ethel M. Albert     

Book Reviews

Book reviewed in this article:
Before the Backbone. Views on the Origin of Vertebrates, by Henry Gee.
Great White Sharks. The Biology ofCarcharodon carcharias, ed. A. Peter Klimley and David G. Ainley.
Social Evolution in Ants, by Andrew F. G. Bourkc and Nigel R. Franks.
The Natural History of Moths, by Mark Young.     

Surface topology of Minibody by selective chemical modifications and mass spectrometry.

The surface topology of the Minibody, a small de novo-designed beta-protein, has been probed by a strategy that combines selective chemical modification with a variety of reagents and mass spectrometric analysis of the modified fragments. Under appropriate conditions, the susceptibility of individual residues primarily depends on their surface accessibility so that their relative reactivities can be correlated with their position in the tertiary structure of the protein. Moreover, this approach provides information on interacting residues, since intramolecular interactions might greatly affect the reactivity of individual side chains by altering their pKa values. The results of this study indicate that, while overall the Minibody model is correct, the beta-sheet formed by the N- and C-terminal segments is most likely distorted. This is also in agreement with previous results that were obtained using a similar approach where mass spectrometry was used to identify Minibody fragments from limited proteolysis (Zappacosta F, Pessi A, Bianchi E, Venturini S, Sollazzo M, Tramontano A. Marino G, Pucci P. 1996. Probing the tertiary structure of proteins by limited proteolysis and mass spectrometry: The case of Minibody. Protein Sci 5:802-813). The chemical modification approach, in combination with limited proteolysis procedures, can provide useful, albeit partial, structural information to complement simulation techniques. This is especially valuable when, as in the Minibody case, an NMR and/or X-ray structure cannot be obtained due to insufficient solubility of the molecule.     

Erratum

Marlene de la Cruz, Fabiola Ramirez and Hector Hernandez (1997)DNA Isolation and Amplification from Cacti. Plant Mol Biol Rep 15:319-325.p. 320: The CTAB extraction buffer should contain 500 mg ascorbic acid and 500 mg DIECA in 100 mL (final concentration of 0.5%).     

石竹科齿瓣无心菜属2新组合名称

基于近年来分子系统学研究结果,石竹科无心菜属(Arenaria L.)齿瓣亚属[subgen.Odontostemma(G.Don)Williams]在属水平的地位得以恢复,该亚属中相关物种名也因此被组合至齿瓣无心菜属(Odontostemma Benth.ex G.Don)之中。然而,中国所产道孚无心菜(A.dawuensis A.J.LiQ.Ban)与神农架无心菜(A.shennongjiaensis Z.E.ZhaoZ.H.Shen)在相关处理中被遗漏,故在此给予其新的组合名称:O.dawuense(A.J.LiQ.Ban)G.Yao和O.shennongjiaense(Z.E.ZhaoZ.H.Shen)G.Yao。     

C. S. Rafinesque’s North American vascular plants at the Academy of Natural Sciences of Philadelphia

Constantine Samuel Rafinesque (1783–1840) proposed about 2700 generic names and over 6700 binomials in approximately 1000 known publications. His herbarium at one time supposedly contained some 50,000 specimens, but after his death part of it was destroyed by rats, and Elias Durand, who eventually purchased the collection, discarded virtually all of the specimens. Because of these circumstances, plant taxonomists have had difficulty in typifying Rafinesque’s names. This paper summarizes the information on the labels of 275 specimens of Rafinesque’s vascular plants from the United States and Canada that are known to exist at the Academy of Natural Sciences in Philadelphia. These specimens come from four sources: (1) Rafinesque’s own herbarium, (2) Charles Wilkins Short’s herbarium, (3) the William Hembel collection, and (4) the herbarium of Rev. Lewis David von Schweinitz. Of the 275 specimens still extant, 51 (18.5%) are considered to be possible types. These type specimens are enumerated with (1) the complete data on the specimen, (2) the original source herbarium, and in most cases (3) the current accepted name of the taxon.     

Cartography in the Traditional African, American, Arctic, Australian, and Pacific Societies.

Cartography in the Traditional African, American, Arctic, Australian, and Pacific Societies. David Woodward and G.Malcolm Lewis. eds. The History of Cartography. Volume 2. Book 3. Chicago: University of Chicago Press. 1998.662 pp.     

Book reviews

Book reviewed in this article: Fruit flies, their biology, natural enemies and control. Volume A. A.S. Robinson and G.H.S. Hooper (eds.). Martin R. Speight and David Wainhouse: Ecology and Management of Forest Insects.     

Multivariable Model-building: A Pragmatic Approach to Regression Analysis Based on Fractional Polynomials for Modelling Continuous Variables by ROYSTON, P. and SAUERBREI, W.

Multivariable Model‐building: A Pragmatic Approach to Regression Analysis Based on Fractional Polynomials for Modelling Continuous Variables (P. Royston and W. Sauerbrei) David W. Hosmer Modern Multivariate Statistical Techniques: Regression, Classification, and Manifold Learning (A. J. Izenman) Debashis Ghosh A Primer on Linear Models (J. F. Monahan) Muni S. Srivastava Mixed Effects Models and Extensions in Ecology with R (A. F. Zuur, E. N. Ieno, N. J. Walker, A. A. Saveliev, and G. M. Smith) Carl James Schwarz Random Effect and Latent Variable Model Selection (D. B. Dunson, Editor) Kenneth Rice Missing Data in Clinical Studies (G. Molenberghs and M. G. Kenward) Suzanne R. Dubnicka Functional and Operatorial Statistics (S. Dabo‐Niang and F. Ferraty, Editors) Jason D. Nielsen Statistical Analysis and Modelling of Spatial Point Patterns (J. Illian, A. Penttinen, H. Stoyan, and D. Stoyan) Jesper Møller Solved Problem in Geostatistics (O. Leuangthong, K. D. Khan, and C. V. Deutsch) Ole F. Christensen Statistical Methods for Environmental Epidemiology with R : A Case Study in Air Pollution and Health (R. D. Peng and F. Dominici) David Buckeridge Correspondence Analysis in Practice, Second Edition (M. Greenacre) Willem Heiser Introduction to Statistical Mediation Analysis (D. P. MacKinnon) Tyler J. VanderWeele Brief Reports by the Editor The EM Algorithm and Extensions, 2nd edition (G. J. McLachlan and T. Krishnan) Probability Models for DNA Sequence Evolution, 2nd edition (R. Durrett) Bayesian Methods for Data Analysis, 3rd edition (B. P. Carlin and T. A. Louis) Nonlinear Regression with R (C. Ritz and J. C. Streibig) Cancer Mortality and Morbidity Patterns in the U.S. Population: An Interdisciplinary Approach (K. G. Manton, I. Akushevich, and J. Kravchenko)     

Book Reviews

Cruel, Poor and Brutal Nations: The Assessment of Mental Health in an Australian Aboriginal Community by Short-stay Psychiatric Field Team Methods . By John Cawte The Jigalong Mob: Aboriginal Victors of the Desert Crusade . By Robert Tonkinson Stone Age Crisis: A Psychiatric Appraisal . By B. G. Burton-Bradley Right and Left: Essays on Dual Symbolic Classification . Edited by Rodney Needham Ohaffia: A Matrilineal Ibo People . By Philip O. Nsugbe Robber Noblemen: A Study of the Political System of the Sikh Jats . By Joyce Pettigrew Max Weber and the Theory of Modern Politics . By David Beetham The Past is Human . By Peter White. Angus and Robertson, Sydney, 1974 Drake's Island of Thieves. Ethnological Sleuthing . By William A. Lessa Lapakahi, Hawaii: Archaeological Studies . Edited by H. David Tuggle and P. Bion Griffin Settlement Patterns in Archaeology . By K. C. Chang Early Chinese Art and its Possible Influence In the Pacific Basin . Edited by Noel Barnard     

Surveying the Rubble: The Transition from State Socialism in Europe

The Curtain Rises: Rethinking Culture, Ideology and the State in Eastern Europe . Hermine G. DeSoto and David G. Anderson , eds.
Symbols, Conflict and Identity: Essays in Political Anthropology . Zdzislaw Mach .     

Brain γ-Glutamyltranspeptidase: Characteristics,development and thyroid hormone dependency of the enzyme in isolated microvessels and neuronal/glial cell plasma membranes

The characteristics, cellular locus and regulation of the enzyme -glutamyltranspeptidase (GT) in brain were examined. In rat brain homogenates, the activity of the enzyme exhibited tissue differences - kidney >>>brain ==testis >>, liver >>skeletal muscle = ventricular muscle and regional differences - brain stem >hippocampus = cerebellum >cerebral cortex, with no significant species/strain differences in the select group of mammals studied. Methods were developed for the isolation from brain of microvessels (MV) and plasma membranes from neuronal/glial cells (N/G PM) utilizing morphological indicators and marker analyses. GT activity was >12 higher in MV than N/G PM; however the enzyme displayed: stability, heat-activation and inhibition with maleate to the same extent in both fractions. A comparative study indicated that in the N/G PM fraction, GT activity was low in all animals studied; GT activity in MV however, was barely detectable in amphibians and reptiles, very low in birds and very high in mammal - mirroring the phylogenetic development of a functional blood-brain barrier. In the rat, GT in both MV and N/G PM displayed a pronounced postnatal increase in activity but the extent and the patterns were different - in all cases, that of the MV greatly exceeded that of the N/G PM and in the MV, the enzyme activity exhibited same pattern as the postnatal development of the blood-brain barrier. The induction of congenital hypothyroidism by propylthiouracil (PTU) had no effect on GT in N/G PM but effected a one third reduction in the activity of GT in MV. The normalization by thyroid hormone replacement indicated that MV GT is under thyroid hormone control. The induction of hypothyroidism by PTU in the adult, however, was without effect on enzyme activity in either fraction. The implications of the thyroid hormone dependency of MV GT in the neonatal period and the relationship of & ggr;GT to the function of the blood brain-barrier is discussed.