title: Characterization of a deep-sea sediment metagenomic clone that produces water-soluble melanin in Escherichia coli.
abstract: To access to the microbial genetic resources of deep-sea sediment by a culture-independent approach, the sediment DNA was extracted and cloned into fosmid vector (pCC1FOS) generating a library of 39,600 clones with inserts of 24-45 kb. The clone fss6 producing red-brown pigment was isolated and characterized. The pigment was identified as melanin according to its physico-chemical characteristics. Subcloning and sequences analyses of fss6 demonstrated that one open reading frame (ORF2) was responsible for the pigment production. The deduced protein from ORF2 revealed significant amino acid similarity to the 4-hydroxyphenylpyruvate dioxygenase (HPPD) from deep-sea bacteria Idiomarina loihiensis. Further study demonstrated that the production of melanin was correlated with homogentistic acid (HGA). The p-hydroxyphenylpyruvate produced by the Escherichia coli host was converted to HGA through the oxidation reaction of introduced HPPD. The results demonstrate that expression of DNA extracted directly from the environment might generate applicable microbial gene products. The construction and analysis of the metagenomic library from deep-sea sediment contributed to our understanding for the reservoir of unexploited deep-sea microorganisms.
authors.affiliation: State Key Laboratory for Biocontrol, Department of Biochemistry, College of Life Sciences, Sun Yat-sen University, Guangzhou 510275, People's Republic of China.
authors.forename: Yali
authors.initials: Y
authors.lastname: Huang
authors.forename: Xintian
authors.initials: X
authors.lastname: Lai
authors.forename: Xiaocui
authors.initials: X
authors.lastname: He
authors.forename: Lixiang
authors.initials: L
authors.lastname: Cao
authors.forename: Zhirui
authors.initials: Z
authors.lastname: Zeng
authors.forename: Jiong
authors.initials: J
authors.lastname: Zhang
authors.forename: Shining
authors.initials: S
authors.lastname: Zhou
mesh_terms: D034241:Alteromonadaceae / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D015723:Gene Library; D023281:Genomics; D019015:Geologic Sediments / Q000382:microbiology*; D008543:Melanins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009792:Oceans and Seas
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D008543:Melanins