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Short description of mercuric reductase from Halocynthiibacter arcticus bacterium genome

Last update on the 16th of October, 2016

Bacteria resistance to heavy metal cations is governed by specialized systems. According to mercury there is a special complex including mercury(II) reductase, commonly known as MerA. It catalyzes the reduction[1] of Hg2+ to Hg0. The main properties of MerA genome organisation[2] in Halocynthiibacter arcticus are presented in table 1.

Table 1. Short description of mercuric reductase from Halocynthiibacter arcticus bacterium genome
Attribute Value
Protein ID AML53752.1
Uniprot AC A0A126V644
Genome fragment ID CP014327.1
Gene location in genome 3843873..3845306
Gene length, bp 1434
Strand Negative
Protein length, aa 477

The aminoacid sequence[2] of mercuric reductase is displayed in fig.1.

Fig. 1. Aminoacid sequence of mercuric redustase in .fasta format
>AML53752.1 mercuric reductase [Halocynthiibacter arcticus]
MPDLLNPNGVDTDTFDLAVIGAGSAGFSAAITAAEDGARVALIGYGTIGGTCVNVGCVPS
KAMIRAVETLHSAKGAARFDGVEATARVTDWAAMVAQKQALVDDLRVAKYVDVLPNYESI
TYIEGQASFAKDGSLHVGGRTICAPKVIIATGSSPHVPDILGLDGIDWLDSTSALEQEQL
PKSLMVMGGGYIGVELAQIFARAGVAVTIVTRRGLLPEAEPEVSAALTKAFADEGIKVLD
GLSYDRFEKSDETVILHAKHNGVAVEIKAEKLMLATGRVPNTGSLALDVAGIDTNARGGI
VIDLQMRSTRDGVYATGDVTGTDQFVYMAAYGAKLAAKNAMNGNTLSYDNSVMPAVVFSD
PQVASVGLTEAQAKTLGYEVVTSVLGLEHVPRALAARDTRGLIKLIAEKDSKKLLGAHII
APEGADSIQTAAMALKMGMTYDDLGAMIFPYLTTVEGLKLAAQTFEKDVAKLSCCAG

Genomic neighbourhood

Proteins involved in one biochemical process are usually encoded closely in one genome fragment. The genomic neighbourhood of MerA made up in NCBI sequence viewer[3] is presented in fig. 2 and also in pdf.

Fig. 2. Genomic neighbourhood of mercuric reductase

Some properties of all proteins[4] presented in fig. 2 are listed in table 2.

Table 2. Mercuric reductase genomic neigbouring proteins properties
Protein ID Protein name Location Strand
AML53751.1 acyl-CoA thioesterase 3843102..3843446 -
AML53752.1 Mercuric reductase 3843873..3845306 -
AML53753.1 Hypothetical protein (contains Transport_MerF region) 3845326..3845508 -
AML53050.1 Mercuric transport protein periplasmic component 3845536..3845832 -
AML53051.1 Mercury transporter MerT 3845844..3846248 -
AML53052.1 MerR family transcriptional regulator 3846323..3846742 +

As it is seen, acyl-CoA tioestherase gene is placed further from MerA than other closely encoded proteins (500bp vs 20-30bp), so it is possible to say that 1) acyl-CoA tioestherase may not be related to mercury reduction and 2) gene sequences of related to reduction proteins may be transcribed into one RNA. Transcriptional regulator is encoded on the opposite DNA strand relatively closely to MerA that may have some sense in bacterium response regulation.

References

  1. Mercury(II) reductase article on Wikipedia;
  2. NCBI Reference Sequence: AML53752.1;
  3. NCBI sequence viewer: CP014327.1:3842941..3846909;
  4. NCBI Reference Sequence: CP014327.1.