Homology modeling of Mycoplasma pneumoniae enolase and its molecular interaction with human plasminogen

Alpha (α)-enolase (e), a glycolytic enzyme, has an alternative role as a surface receptor of several bacteria mediating plasminogen (pg) binding. It is also recognized as a virulence factor of some pathogenic bacteria facilitating plasminogen activation and host cell invasion. A mycoplasmal α-enolase is also a plasminogen binding protein. Molecular interactions of enolase from Mycoplasma pneumoniae with host plasminogen would be useful for exploring the pathogen-host interaction. In an attempt to identify plasminogen binding sites of M. pneumoniae enolase, homology modeling and docking studies were conducted to obtain modeled structures of the M. pneumoniae enolase-plasminogen complex. The refined model was validated further by standard methods. Molecular docking revealed hydrogen bonding of eLys70-pgTyr50, eAsn165-pgThr66, eAla168-pgGlu21, eAsp17-pgLys70, and eAsn213-pgPro68/pgAsn69. Substantial decreases in accessible surface area (ASA) were observed and in concurrence with hydrogen bond pattern. These findings provide a detailed prediction of key residues that interact at the protein-protein interface. Our theoretical prediction is consistent with known biochemical data. The predicted interaction complex can be of great assistance in understanding structural insights, which is necessary to pathogen and host-component interaction. The ability of M. pneumoniae enolase to bind plasminogen may be indicative of an important role in invasion of this pathogen to host.     

Draft genome sequence of Arthrospira platensis C1 (PCC9438)

Arthrospira platensis is a cyanobacterium that is extensively cultivated outdoors on a large commercial scale for consumption as a food for humans and animals. It can be grown in monoculture under highly alkaline conditions, making it attractive for industrial production. Here we describe the complete genome sequence of A. platensis C1 strain and its annotation. The A. platensis C1 genome contains 6,089,210 bp including 6,108 protein-coding genes and 45 RNA genes, and no plasmids. The genome information has been used for further comparative analysis, particularly of metabolic pathways, photosynthetic efficiency and barriers to gene transfer.