ABSTRACT
Mexicain is a 23.8 kDa cysteine protease from the tropical plant Jacaratia mexicana. It is isolated as the most abundant product after cation-exchange chromatography of the mix of proteases extracted from the latex of the fruit. The purified enzyme inhibited with E-64 [N-(3-carboxyoxirane-2-carbonyl)-leucyl-amino(4-guanido)butane] was crystallized by sitting-drop vapour diffusion and the structure was solved by molecular replacement at 2.1 A resolution and refined to an R factor of 17.7% (R(free) = 23.8%). The enzyme belongs to the alpha+beta class of proteins and the structure shows the typical papain-like fold composed of two domains, the alpha-helix-rich (L) domain and the beta-barrel-like (R) domain, separated by a groove containing the active site formed by residues Cys25 and His159, one from each domain. The four monomers in the asymmetric unit show one E-64 molecule covalently bound to Cys25 in the active site and differences have been found in the placement of E-64 in each monomer.
Subject(s)
Papain/chemistry , Amino Acid Sequence , Binding Sites , Chromatography, High Pressure Liquid , Chromatography, Ion Exchange , Crystallization , Crystallography , Electrophoresis, Polyacrylamide Gel , Hydrogen Bonding , Models, Molecular , Molecular Sequence Data , Molecular Structure , Sequence Homology, Amino AcidABSTRACT
Mexicain is a 23.7 kDa papain-like cysteine protease from the tropical plant Jacaratia mexicana. Extracted as a mix of proteases from the latex of the fruit, mexicain is isolated after cation-exchange chromatography as the most abundant product. The purified product inhibited with E-64 was crystallized by sitting-drop vapour diffusion in the presence of ethanolamine. Cryoprotected crystals diffracted X-rays from a home source to 1.98 A and belong to the monoclinic space group P2(1), with unit-cell parameters a = 57.36, b = 90.45, c = 80.39 A, beta = 92.64 degrees . The asymmetric unit contains four molecules of mexicain, with a corresponding crystal volume per protein weight (V(M)) of 2.24 A(3) Da(-1) and a solvent content of 45% by volume. A molecular-replacement model has been determined and refinement is in progress.
Subject(s)
Caricaceae/enzymology , Cysteine Endopeptidases/chemistry , Plant Proteins/chemistry , Crystallization , Crystallography, X-Ray , Cysteine Endopeptidases/isolation & purification , Plant Proteins/isolation & purificationABSTRACT
The aim of this study was to evaluate the prevalence and need for treatment of temporomandibular disorders (TMD) in students living in Bauru, Brazil. The role of occlusal and emotional factors was also addressed. The presence and severity of TMD was determined by using a self-reported anamnestic questionnaire composed of 10 questions regarding common TMD symptoms. The symptoms were transposed into a severity classification according to the number and frequency of positive responses. Occlusal evaluation included an analysis of retruded contact position, intercuspal position, anterolateral guidance, and nonworking side contacts during mandibular movements. Palpation of the muscles and temporomandibular joints were performed to detect clinical signs of TMD. A chi square test was used to compare clinical and occlusal data with the presence and severity of TMD. A total of 0.65% of the subjects had severe TMD symptoms, 5.81% had moderate symptoms, and 34.84% had mild symptoms. Those with severe and moderate symptom levels were interpreted to be in need of treatment. Symptoms were found significantly more frequently in females than in males (P < .01). Self-reported emotional tension and parafunctional habits demonstrated strong associations with TMD (P < .01). Occlusion did not seem to influence the presence or severity of TMD. Based on these results, the efficacy of some traditional TMD treatments should be reconsidered, and reversible and conservative procedures should be the first choice for managing TMD patients.
