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The Cia5 Gene Controls Formation Of The Carbon Concentrating Mechanism In Chlamydomonas Reinhardtii, Youbin Xiang, Jun Zhang, Donald P. Weeks

Department of Biochemistry: Faculty Publications

Wild-type Chlamydomonas reinhardtii cells shifted from high concentrations (5%) of CO2 to low, ambient levels (0.03%) rapidly increase transcription of mRNAs from several CO₂-responsive genes. Simultaneously, they develop a functional carbon concentrating mechanism that allows the cells to greatly increase internal levels of CO₂ and HCO₃. The cia5 mutant is defective in all of these phenotypes. A newly isolated gene, designated Cia5, restores transformed cia5 cells to the phenotype of wild-type cells. The 6,481-bp gene produces a 5.1-kb mRNA that is present constitutively in light in high and low CO₂ both in …

C3 Origins Of The C4 Pathway Regulatory Enzyme, Ppdk-Rp, C. J. Chastain, Gautam Sarath, Raymond Chollet

Gautam Sarath Publications

A current view of C₄ and CAM evolution holds that all of the constituent enzymes of the C₄ pathway preexisted in C₃ plants, albeit functioning in nonphotosynthetic capacities.

Effects Of Antimetabolites On Sclerotium Rolfsii Growth And Oxalic Acid Production, Ezikiel Okafor-Agilo

Seton Hall University Dissertations and Theses (ETDs)

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Identification Of The Domains Of Urer, An Arac-Like Transcriptional Regulator Of The Urease Gene Cluster In Proteus Mirabilis, Carrie A. Poore, Christopher Coker, Jonathan D. Dattelbaum, Harry L.T. Mobley

Chemistry Faculty Publications

Proteus mirabilis urease catalyzes the hydrolysis of urea to CO₂ and NH₃, resulting in urinary stone formation in individuals with complicated urinary tract infections. UreR, a member of the AraC family, activates transcription of the genes encoding urease enzyme subunits and accessory proteins, ureDABCEFG, as well as its own transcription in the presence of urea. Based on sequence homology with AraC, we hypothesized that UreR contains both a dimerization domain and a DNA-binding domain. A translational fusion of the leucine zipper dimerization domain (amino acids 302 to 350) of C/EBP and the C-terminal half of UreR …

Group Viii Spiroplasma Of Costa Rica, Kimberly M. Stewart

College of Graduate Studies: Theses & Dissertations (1964–2006)

Spiroplasma bacteria isolates are classified or identified through a series of serological tests that normally consists of screening, one-way deformation tests, cloning, antisera production, and reciprocal deformation tests. Serological tests on the spiroplasmas are followed by molecular analysis. The standard molecular analysis used for spiroplasmas has been 16S rRNA sequencing. The primary goal ofmy research was to evaluate serologically Group VIII spiroplasmas isolated from tropical Costa Rican tabanids (Diptera: Tabanidae) and to compare them to the temperate North American Group VIII spiroplasmas. A secondary goal was to evaluate both the temperate and tropical Group VIII strains by sequencing the 16S-23S …

An Investigation Of Captive Florida Manatee (Trichecus Manatus Latirostris) Behavior And Social Interactions, Jennifer Sadler Young

College of Graduate Studies: Theses & Dissertations (1964–2006)

Human impacts such as pollution, habitat alteration, and boating have caused many injuries and deaths of the Florida manatee, Trichechus manutus latirostris. Rehabilitation centers have been established in Florida to help return sick or injured manatees back to the wild. Manatees that are released back to the wild after undergoing rehabilitation in captivity might lose some of their abilities to survive in the wild. A factor that might alter behavior in captive individuals was examined by determining if length of time spent in captivity influenced the behavior of manatees during rehabilitation. Even though all facilities follow similar guidelines, invariable …

The Prevalence Of Human Granulocytic Ehrlichiae In Ixodes Scapularis Ticks In Southeastern Georgia, Heather Anne Merten

College of Graduate Studies: Theses & Dissertations (1964–2006)

Human granulocytic ehrlichiosis (HGE) is a newly emerging, tick-borne zoonosis in North America. The agent that causes HGE is very similar to Ehrlichia phagocytophilia and Ehrlichia equi, but has yet to be classified as a separate species.

This study was carried out in order to determine the prevalence rate of HGE infection in blacklegged ticks (Ixodes scapularis) in insular and mainland sites in southeastern Georgia using nested PCR techniques. Four locations were studied representing 2 barrier islands and 2 mainland sites. We hypothesized that areas that have low levels of human disturbance and are somewhat isolated will …

A Comparative Study Of The Reproductive Biology Of Sympatric Morning Glories (Ipomoea-Convolvulaceae), Dexter R. Sowell Ii

College of Graduate Studies: Theses & Dissertations (1964–2006)

Despite the astounding diversity of flowering plants and of mobile organisms that serve as pollinators, sympatric co-flowering plants can potentially share pollinators with each other. This places two selection pressures on plants. First, plants compete for pollinators to visit their flowers and secondly, entice pollinators to be faithful (specialized) and visit only other members of their species. I tested whether sympatric co-flowering plants reduced their selection pressures via temporal partitioning or differential attraction of pollinators using six closely related, sympatric co-flowering morning glories (Ipomoea-Convolvulaceae).

Diurnal flower phenology tightly overlapped, which did not facilitate temporal partitioning of pollinators. However, …

Chemical Constituents Of Desmos Dumosus, Roxb., Mazdida Sulaiman

Student Works (2000-2009)

The chemical content of the 'leaves and bark of Des mos dumosus has been carried out in this study. The leaves yielded nine isoquinoline type of alkaloids and two flavones. The isoquinoline alkaloids isolated were pronuciferine 37, stepharine 39, nomuciferine 40, (-) - 3 - hydroxynomuciferine 41, norlirioferine 42, asimilobine 43, liriodenine 44, lysicamine 45 and O - methylmoschatoline 46. The flavones were 5 - hydroxy - 6,7 - dimethoxyflavone 47 and 5 - hydroxy - 7,8 - dimethoxyflavone 48. The same flavones, 47 and 48 and the alkaloids 45 and 46 were also present in the bark of this …

An Enzymatic Method For The Measurement Of Magnesium, Joseph Murphy

Theses

Magnesium is quantitatively the most important intracellular divalent cation (4), and has been found to serve in a wide range of enzymatic reactions (2). Studies have shown that up to ten percent of hospital patients may have hypomagnesaemia (6).

Atomic absorption spectrophotometry (AAS) under highly specified conditions is the de facto reference method for magnesium measurement but only about ten per cent of laboratories routinely use this method (4). This is because AAS is time-consuming, requires specialised equipment and a certain level of expertise, and may be hazardous due to the use of inflammable gases. Colourimetric methods e.g. calmagite are …

Characterization Of The Human Cytomegalovirus Ul75 Late Gene Promoter, Bernard J. P. Mcwatters

Theses and Dissertations in Biomedical Sciences

Gene expression during productive infection by the human cytomegalovirus (HCMV) occurs in an ordered and sequential manner, beginning with immediate early (IE), then early (E) and finally late (L) gene expression. Significant work has addressed the regulation of IE and E gene expression while relatively little work has addressed the control of late gene expression. In order to further address HCMV late gene expression, the promoter of the HCMV UL75 (glycoprotein H, gH) late gene was characterized. The data obtained in this study were combined with observations made in two other studies that have addressed HCMV late gene expression to …

Characterization Of The Biological Activities Of Recombinant Fusion Protein Green Fluorescent Protein/Human Zona Pellucida Protein 3 (Gfp/Hzp3), Zhiyong Lin

Theses and Dissertations in Biomedical Sciences

Despite numerous reports indicating the successful production of bioactive recombinant ZP3, no report has shown the rhZP3 having direct binding activity with human sperm. Recombinant ZP3 generated from our previous study displayed binding activity with human sperm through indirect evidence from hemizona assay (HZA).

This present study focused on the production of recombinant ZP3 with direct binding activity with human sperm. Through the application of a pEGFP expression vector, fusion protein GFP/ZP3 was successfully generated and expressed. The expression of GFP/ZP3 was evidenced by RT-PCR and western blot. The fusion protein was partially purified by Ni-NTA affinity column from cell …

Immobolisation And Biochemical Characterisation Of A Selected Commercially Available Laccase, Chandra Sundaralingam

Student Works (2000-2009)

ln this study, laccase from Novo Nordisk was chosen for biochemical characterization and immobilization investigation. The specific aims of this work was to develop optimum conditions for immobilization of laccase by entrapment method using copper alginate and characterize the laccase biochemically. The pH optimum of the crude enzyme extract was 5.5 and was found to be stable over a wide range of pH values. The apparent molecular weight of this enzyme was around 79,000 Daltons. Three peaks of activity (isoenzymes) were obtained from isoelectric focusing of pH values 4.7, 5.2 and 6.0. The optimum pH of the immobilized laccase by …

Glucocorticoid Regulation Of Insulin Like Growth Factor Binding Protein-5 Gene Transcription In Human Osteoblasts, Xiaoying Wang

Loma Linda University Electronic Theses, Dissertations & Projects

Glucocorticoids (GCs) inhibit bone formation in vivo and inhibit osteoblast proliferation and collagen synthesis in vitro. These effects may be mediated by alterations in the insulin-like growth factor (IGF) system. In the present study of normal human osteoblast-like (HOB) cells, we tested the hypothesis that dexamethasone (Dex) inhibits the expression of IGF binding protein-5 (IGFBP-5). Dex decreased IGFBP-5 mRNA levels to 54% of control after 4 hr. Dex did not modify the decay of IGFBP-5 mRNA in transcriptionally arrested osteoblast cells. Dex decreased IGFBP-5 hnRNA levels to 67% of control after 2 hr, and the activity of the human IGFBP- …

Ryanodine Receptor Adaptation, Michael Fill, A. Zahradníková, Carlos A. Villalba-Galea, I. Zahradník, A. L. Escobar, S. Györke

School of Pharmacy Faculty Articles

In the heart, depolarization during the action potential activates voltage-dependent Ca²⁺ channels that mediate a small, localized Ca²⁺ influx (I_Ca). This small Ca²⁺ signal activates specialized Ca²⁺ release channels, the ryanodine receptors (RyRs), in the sarcoplasmic reticulum (SR). This process is called Ca²⁺-induced Ca²⁺ release (CICR). Intuitively, the CICR process should be self-regenerating because the Ca²⁺ released from the SR should feedback and activate further SR Ca²⁺ release. However, the CICR process is precisely controlled in the heart and, consequently, some sort of negative control mechanism(s) must exist to …

Studies On The Purification And Role Of Igfbp-5 Protease In Bone, H. Garrett Rush Thompson

Loma Linda University Electronic Theses, Dissertations & Projects

Osteoporosis is a disease characterized by low bone density and deterioration of mineralized bone leading to enhanced susceptibility to fracture. Several growth factors have been implicated in the coupling of formation to resorption during the bone remodeling process. The net bone forming activity of many growth factors has prompted numerous studies focused on the regulation of osteoblast cell proliferation, differentiation and activity. The current study focuses on the insulin-like growth factor (IGF) system, an important growth factor system involved in the regulation of bone formation and bone resorption.

IGF binding protein -5 (IGFBP-5), the most abundant IGF binding protein in …

Hybridization Of Dna By Sequential Immobilization Of Oligonucleotides At The Air-Water Interface, Murali Sastry, Vidya Ramakrishnan, Mrunalini Pattarkine, Anand Gole, K. N. Ganesh

Faculty Works

The hybridization of DNA by sequential electrostatic and hydrogen-bonding immobilization of single-stranded complementary oligonucleotides at the air-water interface with cationic Langmuir monolayers is demonstrated. The complexation of the single-stranded DNA molecules with octadecylamine (ODA) Langmuir monolayers was followed in time by monitoring the pressure-area isotherms. A large (and slow) expansion of the ODA monolayer was observed during each stage of complexation in the following sequence: primary single-stranded DNA followed by complementary single-stranded DNA followed by the intercalator, ethidium bromide. Langmuir-Blodgett (LB) films of the ODA-DNA complex were formed on different substrates and characterized using quartz-crystal microgravimetry (QCM), Fourier transform infrared …

Structure-Expression Relationships Of The 15-Kda Selenoprotein Gene, Easwari Kumaraswamy, Andrey Malyhk, Konstantin V. Korotkov, Sergei Kozyavkin, Yajun Hu, Byeong J. Lee, Dolph L. Hatfield, Alan M. Diamond, Vadim N. Gladyshev

Vadim Gladyshev Publications

Selenium has been implicated in cancer prevention, but the mechanism and possible involvement of selenoproteins in this process are not understood. To elucidate whether the 15-kDa selenoprotein may play a role in cancer etiology, the complete sequence of the human 15-kDa protein gene was determined, and various characteristics associated with expression of the protein were examined in normal and malignant cells and tissues. The 51-kilobase pair gene for the 15-kDa selenoprotein consisted of five exons and four introns and was localized on chromosome 1p31, a genetic locus commonly mutated or deleted in human cancers. Two stemloop structures resembling selenocysteine insertion …

Amino Acid Osmolytes In Regulatory Volume Decrease And Isovolumetric Regulation In Brain Cells: Contribution And Mechanisms, Herminia Pasantes-Morales, Rodrigo Franco, M. Eugenia Torres-Marquez, Karla Hernandez-Fonseca, Arturo Ortega

School of Veterinary and Biomedical Sciences: Faculty Publications

Brain adaptation to hyposmolarity is accomplished by loss of both electrolytes and organic osmolytes, including amino acids, polyalcohols and methylamines. In brain in vivo, the organic osmolytes account for about 35% of the total solute loss. This review focus on the role of amino acids in cell volume regulation, in conditions of sudden hyposmosis, when cells respond by active regulatory volume decrease (RVD) or after gradual exposure to hyposmotic solutions, a condition where cell volume remains unchanged, named isovolumetric regulation (IVR). The amino acid efflux pathway during RVD is passive and is similar in many respects to the volume-activated anion …

Method And Apparatus For Adaptive Filtering By Counting Acoustic Sample Zeroes In Ultrasound Imaging, Gregory R. Bashford, Edward D. Nonnweiler, David D. Becker, David John Muzilla

Biomedical Imaging and Biosignal Analysis Laboratory

An ultrasound imaging system having an adaptive spatial filter the filter coefficients of which, for particular image parameter sample, are determined by counting the number of neighboring image parameter samples having zero or near-zero values. If the number of zero or near-zero values in a data window is greater than a predetermined threshold, the data in the window is passed, not filtered. This filter has two advantages over other spatial filters. First, image parameter data samples having only zero or near-zero neighboring values (i.e., isolated "point noise") are not smeared. Second, boundaries such as the edge of color in a …

Structural And Functional Conservation At The Boundaries Of The Chicken Β-Globin Domain, Noriko Saitoh, Adam C. Bell, Felix Recillas-Targa, Adam G. West, Melanie A. Simpson, Michael Pikaart, Gary Felsenfeld

Department of Biochemistry: Faculty Publications

We show that the 3' boundary of the chicken β -globin locus bears striking structural similarities to the 5' boundary. In erythroid cells a clear transition in DNase I sensitivity of chromatin at the 3' end of the locus is observed, the location of this transition is marked by a constitutive DNase I hypersensitive site (HS), and DNA spanning this site has the enhancer-blocking capacity of an insulator. This HS contains a binding site for the transcription factor CTCF. As in the case of the 5' insulator, the CTCF site is both necessary and sufficient for the enhancer-blocking activity of …

Nonsteroidal Anti-Inflammatory Drugs, Acetaminophen, Cyclooxygenase 2, And Fever, Daniel L. Simmons, David Wagner, Kenneth Westover

Faculty Publications

Nonsteroidal anti-inflammatory drugs (NSAIDs) are frequently used antipyretic agents that most probably exert their antifever effect by inhibiting cyclooxygenase (COX)–2. Thus, COX-2–selective drugs or null mutation of the COX-2 gene reduce or prevent fever. Acetaminophen is antipyretic and analgesic, as are NSAIDs, but it lacks the anti-inflammatory and anticoagulatory properties of these drugs. This has led to the speculation that a COX variant exists that is inhibitable by acetaminophen. An acetaminophen-inhibitable enzyme is inducible in the mouse J774.2 monocyte cell line. Induction of acetaminophen-inhibitable prostaglandin E2 synthesis parallels induction of COX-2. Thus, inhibition of pharmacologically distinct COX-2 enzyme activity by …

Induction Of Apoptosis In Human Prostate Cancer Cells By Resveratrol, Gary Zulfikar Morris

Chemistry & Biochemistry Theses & Dissertations

Recently attention has been brought to trans-resveratrol's {TR) anticancer activity, as determined through a number of cultured cancer cell models. This activity was attributed to TR behaving as an estrogen, and the orientation of TR' s hydroxyl groups. Based on this work it was of interest to determine whether TR would also be toxic in prostate cancer cells; if toxic, did TR induce necrosis or apoptosis in the cells; was it toxic through hormone mediated pathways; and were TR's hydroxyl groups responsible for its biological activity. To this end, cellular viability was assessed in two different prostate cancer cell …

Measurements Of Excess O3, Co2, Co, Ch4, C2h4, C2h2, Hcn, No, Nh3, Hcooh, Ch3cooh, Hcho, And Ch3oh In 1997 Alaskan Biomass Burning Plumes By Airborne Fourier Transform Infrared Spectroscopy (Aftir), Jon G. Goode, Robert J. Yokelson, Darold E. Ward, Ronald A. Susott, Ronald E. Babbitt, Mary Ann Davies, Wei Min Hao

Chemistry and Biochemistry Faculty Publications

We used an airborne Fourier transform infrared spectrometer (AFTIR), coupled to a flow-through, air-sampling cell, on a King Air B-90 to make in situ trace gas measurements in isolated smoke plumes from four, large, boreal zone wildfires in interior Alaska during June 1997. AFTIR spectra acquired near the source of the smoke plumes yielded excess mixing ratios for 13 of the most common trace gases: water, carbon dioxide, carbon monoxide, methane, nitric oxide, formaldehyde, acetic acid, formic acid, methanol, ethylene, acetylene, ammonia and hydrogen cyanide. Emission ratios to carbon monoxide for formaldehyde, acetic acid, and methanol were 2.2±0.4%, 1.3±0.4%, and …

Identification And Characterization Of The Cis-Acting Elements Around The Murine Cd4 Cnhancer, Xin Dong

Loma Linda University Electronic Theses, Dissertations & Projects

The cluster determinant 4 (CD4) molecule is a transmembrane glycoprotein. CD4 is essential for normal T helper cell function and plays an important role in T cell development and activation. CD4 is encoded by a single gene located on chromosome 6 in the mouse and chromosome 12 in the human. Both human and murine CD4 genes are divided into ten exons spanning more than 25 kb and have a large non-coding region in the first and third intron. CD4 gene expression is controlled primarily at the transcriptional level during T cell development and activation.

An enhancer has been identified approximately …

Molecular Cloning And Analysis Of The Modification Genes Of The Kpnbl Restriction- Modification System Of Klebsiella Pneumoniae Strain Gm236, Vernon Robert Chin

Loma Linda University Electronic Theses, Dissertations & Projects

The KpnBl restriction-modification (R-M) system has been recognized for some time in Klebsiella pneumoniae strain GM236. Previously the restriction subunit (hsdR_kpmBI) was cloned and sequenced, based on the sequence infonnation the KpnBl RM system was suspected to be either a type I or type III R-M system In this project the modification genes of KpnBl were cloned into a pMECA plasmid by using a modification expression method. The modification genes were identified on an 8.2 kb EcoRl fragment from a chromosomal library of the GM236 strain. The complete 8.2 kb fragment was sequenced and …

Crystal Structure Of A Nonsymbiotic Plant Hemoglobin, Mark S. Hargrove, Eric Allen Brucker, Boguslaw Stec, Gautam Sarath, Raúl Arredondo-Peter, Robert V. Klucas, John S. Olson, George N. Phillips Jr.

Gautam Sarath Publications

Background: Nonsymbiotic hemoglobins (nsHbs) form a new class of plant proteins that is distinct genetically and structurally from leghemoglobins. They are found ubiquitously in plants and are expressed in low concentrations in a variety of tissues including roots and leaves. Their function involves a biochemical response to growth under limited O₂ conditions.
Results: The first X-ray crystal structure of a member of this class of proteins, riceHb1, has been determined to 2.4 Å resolution using a combination of phasing techniques. The active site of ferric riceHb1 differs significantly from those of traditional hemoglobins and myoglobins. The proximal and distal …

The Peroxisome Proliferator-Activated Receptor Alpha (Ppar ) Regulates Bile Acid Biosynthesis., Mary Hunt, Yi-Zeng Yang, Gosta Eggertsen, Claes Carneheim, Mats Gafvels, Curt Einarsson, Stefan Alexson

Articles

Fibrates are a group of hypolipidemic agents which efficiently lower serum triglyceride levels by affecting the expression of many genes involved in lipid metabolism. These effects are exerted via the peroxisome proliferator-activated receptor alpha (PPARa). In addition, fibrates also lower serum cholesterol levels, suggesting a possible link between the PPARa and cholesterol metabolism. Bile acid formation represents an important pathway for elimination of cholesterol, and the sterol 12a-hydroxylase is a branch-point enzyme in the bile acid biosynthetic pathway, which determines the ratio of cholic acid to chenodeoxycholic acid. Treatment of mice for one week with the peroxisome proliferator WY-14,643 or …

Prolonged Cyclooxygenase-2 Induction In Neurons And Glia Following Traumatic Brain Injury In The Rat, Kenneth I. Strauss, Mary F. Barbe, Renee Marshall Demarest, Ramesh Raghupathi, Samir Mehta, Raj K. Narayan

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Cyclooxygenase-2 (COX2) is a primary inflammatory mediator that converts arachidonic acid into precursors of vasoactive prostaglandins, producing reactive oxygen species in the process. Under normal conditions COX2 is not detectable, except at low abundance in the brain. This study demonstrates a distinctive pattern of COX2 increases in the brain over time following traumatic brain injury (TBI). Quantitative lysate ribonuclease protection assays indicate acute and sustained increases in COX2 mRNA in two rat models of TBI. In the lateral fluid percussion model, COX2 mRNA is significantly elevated (>twofold, p < 0.05, Dunnett) at 1 day postinjury in the injured cortex and bilaterally in the hippocampus, compared to sham-injured controls. In the lateral cortical impact model (LCI), COX2 mRNA peaks around 6 h postinjury in the ipsilateral cerebral cortex (fivefold induction, p < 0.05, Dunnett) and in the ipsilateral and contralateral hippocampus (two- and six-fold induction, respectively, p < 0.05, Dunnett). Increases are sustained out to 3 days postinjury in the injured cortex in both models. Further analyses use the LCI model to evaluate COX2 induction. Immunoblot analyses confirm increased levels of COX2 protein in the cortex and hippocampus. Profound increases in COX2 protein are observed in the cortex at 1-3 days, that return to sham levels by 7 days postinjury (p < 0.05, Dunnett). The cellular pattern of COX2 induction following TBI has been characterized using immunohistochemistry. COX2-immunoreactivity (-ir) rises acutely (cell numbers and intensity) and remains elevated for several days following TBI. Increases in COX2-ir colocalize with neurons (MAP2-ir) and glia (GFAP-ir). Increases in COX2-ir are observed in cerebral cortex and hippocampus, ipsilateral and contralateral to injury as early as 2 h postinjury. Neurons in the ipsilateral parietal, perirhinal and piriform cortex become intensely COX2-ir from 2 h to at least 3 days postinjury. In agreement with the mRNA and immunoblot results, COX2-ir appears greatest in the contralateral hippocampus. Hippocampal COX2-ir progresses from the pyramidal cell layer of the CA1 and CA2 region at 2 h, to the CA3 pyramidal cells and dentate polymorphic and granule cell layers by 24 h postinjury. These increases are distinct from those observed following inflammatory challenge, and correspond to brain areas previously identified with the neurological and cognitive deficits associated with TBI. While COX2 induction following TBI may result in selective beneficial responses, chronic COX2 production may contribute to free radical mediated cellular damage, vascular dysfunction, and alterations in cellular metabolism. These may cause secondary injuries to the brain that promote neuropathology and worsen behavioral outcome.

Crystallization And Structure Determination Of The Catalytic Trimer Of Methanococcus Jannaschii Aspartate Transcarbamoylase, Jacqueline Vitali, Tatyana Vorobyova, Gordon Websterb, Evan R. Kantrowitza

Physics Faculty Publications

Aspartate transcarbamoylase (ATCase) catalyzes the first step in the pyrimidine biosynthetic pathway, the reaction between carbamoyl phosphate and L-aspartate to form N-carbamoyl-L-aspartate and phosphate. The structural analysis of the ATCase catalytic trimer from Methanococcus jannaschii, a unicellular thermophilic archaeabacterium, has been undertaken in order to gain insight into the structural features that are responsible for the thermostability of the enzyme. As a first step, the catalytic trimer was crystallized in space group R32, with unit-cell parameters a = b = 265.3, c = 195.5 Å and two trimers in the asymmetric unit. Its structure was determined using …