Sequence analysis and confirmation of the type IV pili-associated proteins PilY1, PilW and PilV in Acidithiobacillus thiooxidans.

Elvia Alfaro-Saldaña,J Alfredo Méndez-Cabañas,Marizel Astello-García,Araceli Hernández-Sánchez,J Viridiana García-Meza,O Araceli Patrón-Soberano,Christian Schönbach

doi:10.1371/journal.pone.0199854

Elvia Alfaro-Saldaña, J Alfredo Méndez-Cabañas + Show 5 more

Open Access

https://doi.org/10.1371/journal.pone.0199854

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Journal: PloS one	Publication Date: Jan 7, 2019
Citations: 4	License type: CC BY 4.0

Affiliation: Autonomous University of San Luis Potosí

Abstract

Acidithiobacillus thiooxidans is an acidophilic chemolithoautotrophic bacterium widely used in the mining industry due to its metabolic sulfur-oxidizing capability. The biooxidation of sulfide minerals is enhanced through the attachment of At. thiooxidans cells to the mineral surface. The Type IV pili (TfP) of At. thiooxidans may play an important role in the bacteria attachment since TfP play a key adhesive role in the attachment and colonization of different surfaces. In this work, we report for the first time the mRNA sequence of three TfP proteins from At. thiooxidans, the adhesin protein PilY1 and the TfP pilins PilW and PilV. The nucleotide sequences of these TfP proteins show changes in some nucleotide positions with respect to the corresponding annotated sequences. The bioinformatic analyses and 3D-modeling of protein structures sustain their classification as TfP proteins, as structural homologs of the corresponding proteins of Ps. aeruginosa, results that sustain the role of PilY1, PilW and PilV in pili assembly. Also, that PilY1 comprises the conserved Neisseria-PilC (superfamily) domain of the tip-associated adhesin, while PilW of the superfamily of putative TfP assembly proteins and PilV belongs to the superfamily of TfP assembly protein. In addition, the analyses suggested the presence of specific functional domains involved in adhesion, energy transduction and signaling functions. The phylogenetic analysis indicated that the PilY1 of Acidithiobacillus genus forms a cohesive group linked with iron- and/or sulfur-oxidizing microorganisms from acid mine drainage or mine tailings.

Highlights

The type IV pili (TfP) of At. thiooxidans may play an important role in the bacterial attachment to mineral surfaces, leading to an increase in the rate of dissolution of sulfide minerals
Cell of 5 days in culture were negative stained with 2% uranyl acetate or 1% phosphotungstic acid (PTA)
We performed a negative staining with 1% PTA, under these conditions, the pili and flagellum were covered by extracellular polymeric substances (EPS) (ii), to prevent that, prior to the staining with 1% PTA cells were washed, both S0 and EPS were eliminated, flagella and most of pili were lost as well

Summary

Introduction

Bioinformatic analyses and 3-D modeling of each of these TfP proteins show that PilY1 is an adhesin whereas PilW and PilV are pilus assembly proteins (structural pilins) of the TfP. Phylogenetic relationships were analyzed for the confirmed nucleotide and protein sequences of PilY1, PilW and PilV from At. thiooxidans ATCC19377 against those of the NCBI database using BLASTN 2.8.0+ [41, 42], and UniProt [43] bioinformatic resources.

Results

Conclusion