User:Maitreyee Mukherjee/Sandbox 1
From Proteopedia
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| - | <applet load=' | + | <applet load='Phb_synthase_1.pdb' size='400' frame='true' align='right' caption='PHB synthase domain amino acids 286 to 547' /> |
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| + | '''INTRODUCTION:''' | ||
''Rhodobacter sphaeroides'' is a metabolically versatile purple photosynthetic α-proteobacteria which produces polyhydroxybutyrate (PHB) as inclusions inside its cell. PHB is a biopolymer which has the properties similar to synthetic polymers such as polyethylene and hence has a potential of being used as a biopolymer. The biochemical pathway for PHB production in this organism is complex and is controlled by the actions of several gene products. PHB synthase or phaC is the gene that is responsible for conversion of the monomeric precursor of PHB R(-)-β-Hydroxybutyryl-CoA into polyhydroxybutyrate. | ''Rhodobacter sphaeroides'' is a metabolically versatile purple photosynthetic α-proteobacteria which produces polyhydroxybutyrate (PHB) as inclusions inside its cell. PHB is a biopolymer which has the properties similar to synthetic polymers such as polyethylene and hence has a potential of being used as a biopolymer. The biochemical pathway for PHB production in this organism is complex and is controlled by the actions of several gene products. PHB synthase or phaC is the gene that is responsible for conversion of the monomeric precursor of PHB R(-)-β-Hydroxybutyryl-CoA into polyhydroxybutyrate. | ||
Revision as of 00:21, 23 April 2009
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INTRODUCTION:
Rhodobacter sphaeroides is a metabolically versatile purple photosynthetic α-proteobacteria which produces polyhydroxybutyrate (PHB) as inclusions inside its cell. PHB is a biopolymer which has the properties similar to synthetic polymers such as polyethylene and hence has a potential of being used as a biopolymer. The biochemical pathway for PHB production in this organism is complex and is controlled by the actions of several gene products. PHB synthase or phaC is the gene that is responsible for conversion of the monomeric precursor of PHB R(-)-β-Hydroxybutyryl-CoA into polyhydroxybutyrate.
FUNCTION:
The enzyme catalyses the conversion of the monomeric precursor of PHB into PHB with the release of CoA. In other words these enzymes mediate the conversion of a soluble substrate into polymerized insoluble inclusions inside the cells of these bacteria. Upon covalent catalysis of polyester chain formation, this soluble enzyme gets converted to amphipathic enzyme (The amphipathic enzyme conjugates are analogous to certain membrane-bound proteins such as cytochrome b, which have been shown to comprise a hydrophilic protein core anchored to a lipid bilayer by a hydrophobic polypeptide tail). Initiation of a self assembly process occurs and this results in the formation of the insoluble cytoplasmic inclusions with a phospholipids monolayer and covalently attached polyester synthases at the surface.
PROPERTIES:
Number of amino acids: 601
Molecular weight: 66831.6
Theoretical pI: 5.63
Amino acid sequence:
1 mateeqspgs grdaqferln anltridels krltaaltkr klsdpalhgp sgdvflkamt
61 aymaemmqnp akilehqisf wgkslkhyve aqhqlvkgel kpppdvtpkd rrfsnplwqt
121 hpffnylkqq ylmnaeavnq avealehiep sdkkrveyfs rqivdlfspt nffgtnpdal
181 eraiatdges lvqglenlvr dieanngdll vtladpeafq vgqnlatteg svvyrnrmfe
241 liqykpttet vhetpllifp pwinkfyild lkpqnsllkw lvdqgftvfv vswvnpdksy
301 agigmddyir egymramaev rsitrqkqin avgyciagtt ltltlahlqk agdpsvrsat
361 ffttltdfsd pgevgvflnd dfvdgierqv avdgildktf msrtfsylrs ndliyqpaik
421 symmgeappa fdllywngdg tnlpaqmave ylrglcqqdr laggtfpvlg spvglkdvtl
481 pvcaiacetd hiapwkssfn gfrqfgstdk tfilsqsghv agivnppsrn kyghytnegp
541 agtpesfreg aefhagswwp rwgawlaers gkqvparqpg dskhpelapa pgsyvaavgg
601 a
Amino acid Composition:
Ala (A) 52 8.7%, Arg (R) 29 4.8%, Asn (N) 26 4.3%, Asp (D) 34 5.7%, Cys (C) 4 0.7%, Gln (Q) 29 4.8%, Glu (E) 35 5.8%, Gly (G) 46 7.7%, His (H) 13 2.2%, Ile (I) 24 4.0%, Leu (L) 54 9.0%, Lys (K) 28 4.7%, Met (M) 14 2.3%, Phe (F) 31 5.2%, Pro (P) 40 6.7%, Ser (S) 36 6.0%, Thr (T) 37 6.2%, Trp (W) 11 1.8%, Tyr (Y) 20 3.3%. Val (V) 38 6.3% Pyl (O) 0 0.0% Sec (U) 0 0.0%
Total number of negatively charged residues (Asp + Glu): 69 Total number of positively charged residues (Arg + Lys): 57
Atomic composition:
Carbon C 3004 Hydrogen H 4612 Nitrogen N 808 Oxygen O 888 Sulfur S 18
Total number of atoms: 9330
Extinction coefficients:
Extinction coefficients are in units of M-1 cm-1, at 280 nm measured in water.
Ext. coefficient 90550 Abs 0.1% (=1 g/l) 1.355, assuming ALL Cys residues appear as half cystines Ext. coefficient 90300 Abs 0.1% (=1 g/l) 1.351, assuming NO Cys residues appear as half cystines
Estimated half-life:
The N-terminal of the sequence considered is M (Met).
The estimated half-life is: 30 hours (mammalian reticulocytes, in vitro). >20 hours (yeast, in vivo). >10 hours (Escherichia coli, in vivo).
Instability index:
The instability index (II) is 41.97 This classifies the protein as unstable.
Aliphatic index: 77.60
Grand average of hydropathicity (GRAVY): -0.330
