Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.8 (FAST)
 758 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Like all c-type lysozymes, those from rainbow trout act as 1,4-beta-acetyl-muramidases to destroy bacteria by cleaving the polysaccharide chains of alternating N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) units in the cell walls. Lysozymes also hydrolyse chitin, the analogous N-acetylglucosamine polymer. The rainbow trout enzymes have been shown to be particularly effective in bacterial defence. We have determined the crystal structures of three complexes between rainbow trout lysozyme (RBTL) and the chito-oligosaccharides (NAG)(2), (NAG)(3) and (NAG)(4) to resolutions of 1.8, 2.0 and 1.6 A, respectively. Crystals of these complexes were obtained by co-crystallization, and intensity data were collected on a FAST area detector system. Refinement and model building gave final R values of 16.6, 15.9 and 16.5% for the di-, tri- and tetrasaccharide complexes, respectively. The results show that the chito-oligosaccharides bind to sites A, B and C as previously observed for complexes between the hen egg-white lysozyme (HEWL) and a variety of saccharides. The NAG ring in site D is not bound so deeply and is only slightly distorted towards a half-chair conformation as observed for the equivalent NAM residue in HEWL. From our results, there is reason to question the position and the degree of strain of the D saccharide and the mode of binding and importance of two saccharides in sites E and F for correct orientation of sugar D and effective hydrolysis of a productive substrate-lysozyme complex. Simple model building study from our structures implies a 'left-sided' binding mode of (NAG)(6) in the lower part of the active site of RBTL.
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PMID:Crystal structures of three complexes between chito-oligosaccharides and lysozyme from the rainbow trout. How distorted is the NAG sugar in site D? 1529 65

Muslims abstain from eating, drinking and smoking from dawn to sunset during the holy month of Ramadan. Prolonged fasting is thought to be among risk factors for many diseases, e.g., cardiovascular, gastrointestinal and various infectious diseases. It could also play a part in several eye diseases, including dry eye syndrome, glaucoma, and cataract. Toxic and oxidative effects due to increased concentrations of some biochemicals as a result of reduction in tear volume thought to play an important role in damaging ocular tissue. Human tear is an important biological fluid similar to blood in many aspects. Tear film is composed of three basic layers i.e. lipid, aqueous and mucin. The tear film covering the ocular surface presents a mechanical and antimicrobial barrier, and endures an optical refractive surface. The aim of this study was to analyze and compare tear protein of volunteers during fasting. Using two reliable analytical methods, i.e. electrophoresis and high performance liquid chromatography (HPLC), we compared tear protein content of sixty volunteers (35 males and 25 females, 23-27 years old) during fasting in holly month of Ramadan (FAST: n = 62) and one month before Ramadan (CTRL: n = 60). The results showed that some identified tear proteins decreased during fasting. On the other hand, the activity of some enzymes such as lysozyme, lactoferrin and alpha amylase also decreased in fasting samples. Electrophoresis results showed that tear protein patterns in FAST (P < 0.05) were different from those of CTRL. There were a few more protein peaks in the FAST group (P < 0.005) than in CTRL.
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PMID:Effect of Ramadan fasting on tear proteins. 2117 27