Clostridium Structure

RB Yelle, N-S Park, T Ichiye. Molecular dynamics simulations of rubredoxm from Clostridium pasteurianum Changes m structure and electrostatic potential during redox reactions. Proteins 22 154-167, 1995. 

I Qumkal, V Davasse, 1 Gaillard, J-M Mouhs. On the role of conserved prohne residues in the structure and function of Clostridium pasteurianum 2[4Ee-4S] ferredoxm. Protein Eng 7 681-687, 1994. 

Another subfamily of ADP-iibosylating toxins modifies G-actin (at Argl77), thereby inhibiting actin polymerization. Members of this family are, for example, C. botulinum C2 toxin and Clostridium perfringens iota toxin. These toxins are binary in structure. They consist of an enzyme component and a separate binding component, which is structurally related to the binding component of anthrax toxin [3]. 

The mechanism whereby the bacteria produce the disease with its attendant symptoms is often due to the cells ability to produce specific poisons, toxins or aggressins (Chapter 14). Many of these are tissue-destroying enzymes which can damage the cellular structure ofthe body or destroy red blood cells. Others (neurotoxins) are highly specific poisons ofthe central nervous system, for example the toxin produced by Clostridium botulinum is, weight for weight, one ofthe most poisonous substances known. 

Kuno S, A Bacher, H Simon (1985) Structure of enoate reductase from a Clostridium tyrobutyricum (C. spec. Lai). Biol Chem Hoppe-Seyler 366 463-472. 

It has been postulated that Chlamydia may produce a heat shock protein that causes tissue damage through a delayed hypersensitivity reaction. C. trachomatis may also possess DNA evidence of toxin-like genes that code for high-molecular-weight proteins with structures similar to Clostridium difficile cytotoxins, enabling inhibition of immune activation. This may explain the observation of a chronic C. trachomatis infection in subclinical PID. 

Hecht G, C Pothoulakis, JT LaMont, JL Madara. (1988). Clostridium difficile toxin A perturbs cytoskeletal structure and tight junction permeability of cultured human intestinal epithelial monolayers. J Clin Invest 82 1516-1524. 

This review will not be concerned with functionally alternative structures and metabolites which appear in iron-limited growth. Thus Clostridium pasteurianum and other bacteria when grown in the presence of iron form ferredoxin grown at low iron the same organisms form flavodoxin, a flavoprotein [Knight, ., Jr., Hardy, R. W. J. Biol. Chem. 242, 1370 (1967) Mayhem, S. G., Massey, V. J. Biol. Chem. 244, 794 (1969)]. 

The crystallographic structure of rubredoxin from Clostridium pasteurianum at 2.5 A, a resolution sufficient to reveal the sequence of several of the bulky amino acid side chains, shows the iron coordinated to two pairs of cysteine residues located rather near the termini of the polypeptide chain (Fig. 1). A related rubredoxin, with a three times larger molecular weight, from Pseudomonas oleovorans is believed to bind iron in a similar fashion. This conclusion is based on physical probes, especially electron paramagnetic resonance spectroscopy, all of which indicate that the iron is in each case situated in a highly similar environment however, the proteins display some specificity in catalytic function. 

Recently Jensen and co-workers have determined the structure of a clostridial-type ferredoxin obtained from Micrococcus aerogenes (47). One of the two apparently identical iron-sulfur clusters is illustrated in Fig. 2. The structure is compatible with a model with iron and labile sulfide at alternate comers of a cube. This accounts for the equivalence of these moieties in the protein. Another 8-iron-8 labile sulfur ferredoxin, from Clostridium acidiurici, similarly contains two independent iron-sulfur clusters per molecule (48). Strahs and Kraut (49) had earlier discovered... 

Antimicrobial resistance to rifamycins develops rapidly both in vitro and in vivo [65,85,86], As a consequence, all the three members of the family (i.e. rifampicin, rifabutin and rifapentine) are used clinically as components of combination therapies [65,87], Being structurally related, rifaximin could share this potential. And indeed resistance rates, recorded in fecal strains of Enterobacteriaceae, Enterococcus, Bacteroides, Clostridium and anaerobic cocci, ranged between 30 and 90% after short-term (5 days) antibiotic (800 mg daily) treatment [82], A similar pattern was observed in 10 patients with hepatic encephalopathy after treatment with rifaximin 1,200 mg/day for 5 days [80]. 

JW. Peters, WN. Lanzilotta, BJ. Lemon, LC. eefeldt (1998) X-ray crystal structure of the Fe-only hydrogenase (CpI) from Clostridium pasteurianum to 1.8 Angstrom resolution. Science, 282 1853-1858... 

Ho, J. G., Greco, A., Rupnik, M., and Ng, K. K. (2005). Crystal structure of receptorbinding C-terminal repeats from Clostridium difficile toxin A. Proc. Natl. Acad. Sci. USA 102, 18373-18378. 

The simplest of these proteins are rubredoxins, which are bacterial proteins having a characteristic red colour (from which their name is derived) containing an FeS4 assembly, consisting of an Fe(III) ion coordinated to four cysteine groups. The typical tetrahedral structure of this group is illustrated in Figure 17 for the rubredoxin isolated from Clostridium pasteurianum (FW 6100).35... 

Figure 17 X-Ray structure of the active site of the rubredoxin from Clostridium pasteurianum...

Meyer, J. and Gagnon, J. (1991) Primary structure of hydrogenase I from Clostridium pas-teurianum. Biochemistry, 30, 9697-704. 

Das A, Hugenholtz J, Van Halbeek H, Ljungdahl LG. 1989. Structure and function of a menaquinone involved in electron transport in membranes of Clostridium thermoaceticum and Clostridium thermoautotrophicum. J Bacteriol 171 5823-9. 

Das A, Ljungdahl LG. 1997. Composition and primary structure of the FiFq ATP synthase from the obhgately anaerobic bacterium Clostridium thermoaceticum. J Bacteriol 179 3746-55. 

Sakaguchi, G., Molecular structure of Clostridium botulinum progenitor toxins, in Portland, A.L., Dowel, V.R. and Richard, I.L., eds.. Microbial Toxins in Foods and Feeds. Cellular and Molecular Modes of Action, Plenum Press, New York, pp. 173-180, 1990. 

Within the cellulosome complex, type I dockerin domain is responsible for incorporating its associated glycosyl hydrolase in the bacterial cellulosome via interaction with a reception domain, the cohesin domain. The three-dimensional solution structure of the 69-residue dockerin domain from the thermophilic Clostridium thermocellum (Topt = 55-65 °C) was solved by NMR and was found to consist of two Ca " -binding loop-helix motifs connected by a linker. Each Ca " -binding subdomain is stabilized by a cluster of buried hydrophobic sidechains. Recently, the NMR sequence-specific resonance assignment of type II cohesin module from C. thermocellum has been published. ... 

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