The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
 
 
 
 
 

Structure, expression, and evolution of a gene encoding the precursor of nisin, a small protein antibiotic.

We have cloned and sequenced a gene (spaN) from Streptococcus lactis ATCC 11454 which encodes the peptide precursor of the small protein antibiotic nisin. The encoded precursor is 57 amino acids long, with a 23-residue leader region and a 34-residue structural region. The structural region contains serines, threonines, and cysteines at exactly the positions required to give mature nisin by a series of post-translational modifications involving dehydration of serines and threonines to dehydro forms, and cross-linking with cysteine residues. S1 mapping revealed a 267-nucleotide transcript of the nisin gene that is expressed during vegetative growth and stationary phase. It has a half-life of 7-10 min. The absence of an identifiable promoter or rho-independent terminator and the detection of two different 5'-ends of the transcript suggested it is a processing product from a larger RNA. This may represent a polycistronic mRNA which may also encode proteins involved in processing the nisin precursor peptide. Open reading frames were found in regions flanking the nisin gene. The one downstream had a ribosome binding site and appeared to be transcribed by read-through from the nisin gene. The one upstream had significant homology to a putative transposase from the Escherichia coli IS2 insertion element. Comparison of gene sequence homologies between nisin and the other lanthionine antibiotics, subtilin and epidermin, indicated that they all evolved from a common ancestor. Corresponding leader peptide sequences showed mediocre amino acid homology, but nearly perfect hydropathic homologies, suggesting a common function. It is proposed that this function includes recognition signals or other information required for post-translational processing.[1]

References

 
WikiGenes - Universities