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Pfeiffer F, Dyall-Smith M. Genome comparison reveals that Halobacterium salinarum 63-R2 is the origin of the twin laboratory strains NRC-1 and R1. Microbiologyopen 2023; 12:e1365. [PMID: 37379421 DOI: 10.1002/mbo3.1365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 05/09/2023] [Accepted: 05/12/2023] [Indexed: 06/30/2023] Open
Abstract
The genome of Halobacterium strain 63-R2 was recently reported and provides the opportunity to resolve long-standing issues regarding the source of two widely used model strains of Halobacterium salinarum, NRC-1 and R1. Strain 63-R2 was isolated in 1934 from a salted buffalo hide (epithet "cutirubra"), along with another strain from a salted cow hide (91-R6T , epithet "salinaria," the type strain of Hbt. salinarum). Both strains belong to the same species according to genome-based taxonomy analysis (TYGS), with chromosome sequences showing 99.64% identity over 1.85 Mb. The chromosome of strain 63-R2 is 99.99% identical to the two laboratory strains NRC-1 and R1, with only five indels, excluding the mobilome. The two reported plasmids of strain 63-R2 share their architecture with plasmids of strain R1 (pHcu43/pHS4, 99.89% identity; pHcu235/pHS3, 100.0% identity). We detected and assembled additional plasmids using PacBio reads deposited at the SRA database, further corroborating that strain differences are minimal. One plasmid, pHcu190 (190,816 bp) corresponds to pHS1 (strain R1) but is even more similar in architecture to pNRC100 (strain NRC-1). Another plasmid, pHcu229, assembled partially and completed in silico (229,124 bp), shares most of its architecture with pHS2 (strain R1). In deviating regions, it corresponds to pNRC200 (strain NRC-1). Further architectural differences between the laboratory strain plasmids are not unique, but are present in strain 63-R2, which contains characteristics from both of them. Based on these observations, it is proposed that the early twentieth-century isolate 63-R2 is the immediate ancestor of the twin laboratory strains NRC-1 and R1.
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Affiliation(s)
- Friedhelm Pfeiffer
- Computational Biology Group, Max-Planck-Institute of Biochemistry, Martinsried, Germany
| | - Mike Dyall-Smith
- Computational Biology Group, Max-Planck-Institute of Biochemistry, Martinsried, Germany
- Veterinary Biosciences, Melbourne Veterinary School, Faculty of Science, University of Melbourne, Parkville, New South Wales, Australia
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Masmoudi F, Alsafran M, Jabri HA, Hosseini H, Trigui M, Sayadi S, Tounsi S, Saadaoui I. Halobacteria-Based Biofertilizers: A Promising Alternative for Enhancing Soil Fertility and Crop Productivity under Biotic and Abiotic Stresses-A Review. Microorganisms 2023; 11:1248. [PMID: 37317222 DOI: 10.3390/microorganisms11051248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 05/03/2023] [Accepted: 05/06/2023] [Indexed: 06/16/2023] Open
Abstract
Abiotic and biotic stresses such as salt stress and fungal infections significantly affect plant growth and productivity, leading to reduced crop yield. Traditional methods of managing stress factors, such as developing resistant varieties, chemical fertilizers, and pesticides, have shown limited success in the presence of combined biotic and abiotic stress factors. Halotolerant bacteria found in saline environments have potential as plant promoters under stressful conditions. These microorganisms produce bioactive molecules and plant growth regulators, making them a promising agent for enhancing soil fertility, improving plant resistance to adversities, and increasing crop production. This review highlights the capability of plant-growth-promoting halobacteria (PGPH) to stimulate plant growth in non-saline conditions, strengthen plant tolerance and resistance to biotic and abiotic stressors, and sustain soil fertility. The major attempted points are: (i) the various abiotic and biotic challenges that limit agriculture sustainability and food safety, (ii) the mechanisms employed by PGPH to promote plant tolerance and resistance to both biotic and abiotic stressors, (iii) the important role played by PGPH in the recovery and remediation of agricultural affected soils, and (iv) the concerns and limitations of using PGHB as an innovative approach to boost crop production and food security.
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Affiliation(s)
- Fatma Masmoudi
- Biotechnology Program, Center for Sustainable Development, College of Art and Sciences, Qatar University, Doha P.O. Box 2713, Qatar
| | - Mohammed Alsafran
- Central Laboratories Unit (CLU), Office of VP for Research & Graduate Studies, Qatar University, Doha P.O. Box 2713, Qatar
- Agricultural Research Station (ARS), Office of VP for Research and Graduate Studies, Qatar University, Doha P.O. Box 2713, Qatar
| | - Hareb Al Jabri
- Biotechnology Program, Center for Sustainable Development, College of Art and Sciences, Qatar University, Doha P.O. Box 2713, Qatar
- Department of Biological and Environmental Sciences, College of Art and Sciences, Qatar University, Doha P.O. Box 2713, Qatar
| | - Hoda Hosseini
- Biotechnology Program, Center for Sustainable Development, College of Art and Sciences, Qatar University, Doha P.O. Box 2713, Qatar
| | - Mohammed Trigui
- Laboratory of Environmental Sciences and Sustainable Development (LASED), Sfax Preparatory Engineering Institute, University of Sfax, Sfax 3018, Tunisia
| | - Sami Sayadi
- Biotechnology Program, Center for Sustainable Development, College of Art and Sciences, Qatar University, Doha P.O. Box 2713, Qatar
| | - Slim Tounsi
- Laboratory of Biopesticides (LBPES), Center of Biotechnology of Sfax, University of Sfax, Sfax 3038, Tunisia
| | - Imen Saadaoui
- Biotechnology Program, Center for Sustainable Development, College of Art and Sciences, Qatar University, Doha P.O. Box 2713, Qatar
- Department of Biological and Environmental Sciences, College of Art and Sciences, Qatar University, Doha P.O. Box 2713, Qatar
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Serrano S, Mendo S, Caetano T. Haloarchaea have a high genomic diversity for the biosynthesis of carotenoids of biotechnological interest. Res Microbiol 2021; 173:103919. [PMID: 34942349 DOI: 10.1016/j.resmic.2021.103919] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 11/27/2022]
Abstract
Haloarchaea are mostly components of the microbial biomass of saline aquatic environments, where they can be a dietary source of heterotrophic metazoans or contribute to flamingo's plumage coloration. The diversity of secondary metabolites (SMs) produced by haloarchaea, which might play multiple ecological roles and have diverse biotechnological applications has been largely understudied. Herein, 67 haloarchaeal complete genomes were analyzed and 182 SMs biosynthetic gene clusters (BGCs) identified that encode the production of terpenes (including carotenoids), RiPPs and siderophores. Terpene BGCs were further analysed and it was concluded that all haloarchaea might produce squalene and bacterioruberin, which one a strong antioxidant. Most of them have other carotenoid BGCs that include a putative β-carotene ketolase that was not characterized so far in haloarchaea, but may be involved with canthaxanthin's biosynthesis. The production of bacterioruberin by Haloferax mediterranei ATCC 33500 was found to be not related to its antimicrobial activity.
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Affiliation(s)
- Susana Serrano
- CESAM and Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Sónia Mendo
- CESAM and Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Tânia Caetano
- CESAM and Department of Biology, University of Aveiro, Aveiro, Portugal.
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Russ B, Pfeiffer F, Dyall-Smith M. Halovirus HF2 Intergenic Repeat Sequences Carry Promoters. Viruses 2021; 13:2388. [PMID: 34960657 DOI: 10.3390/v13122388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 11/25/2021] [Accepted: 11/26/2021] [Indexed: 11/16/2022] Open
Abstract
Halovirus HF2 was the first member of the Haloferacalesvirus genus to have its genome fully sequenced, which revealed two classes of intergenic repeat (IR) sequences: class I repeats of 58 bp in length, and class II repeats of 29 bp in length. Both classes of repeat contain AT-rich motifs that were conjectured to represent promoters. In the present study, nine IRs were cloned upstream of the bgaH reporter gene, and all displayed promoter activity, providing experimental evidence for the previous conjecture. Comparative genomics showed that IR sequences and their relative genomic positions were strongly conserved among other members of the same virus genus. The transcription of HF2 was also examined by the reverse-transcriptase-PCR (RT-PCR) method, which demonstrated very long transcripts were produced that together covered most of the genome, and from both strands. The presence of long counter transcripts suggests a regulatory role or possibly unrecognized coding potential.
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Dyall-Smith M, Pfeiffer F, Chiang PW, Tang SL. The Novel Halovirus Hardycor1, and the Presence of Active (Induced) Proviruses in Four Haloarchaea. Genes (Basel) 2021; 12:149. [PMID: 33498646 DOI: 10.3390/genes12020149] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 12/15/2022] Open
Abstract
The virus Hardycor1 was isolated in 1998 and infects the haloarchaeon Halorubrum coriense. DNA from a frozen stock (HC1) was sequenced and the viral genome found to be 45,142 bp of dsDNA, probably having redundant, circularly permuted termini. The genome showed little similarity (BLASTn) to known viruses. Only twenty-two of the 53 (41%) predicted proteins were significantly similar to sequences in the NCBI nr protein database (E-value ≤ 10-15). Six caudovirus-like proteins were encoded, including large subunit terminase (TerL), major capsid protein (Mcp) and tape measure protein (Tmp). Hardycor1 was predicted to be a siphovirus (VIRFAM). No close relationship to other viruses was found using phylogenetic tree reconstructions based on TerL and Mcp. Unexpectedly, the sequenced virus stock HC1 also revealed two induced proviruses of the host: a siphovirus (Humcor1) and a pleolipovirus (Humcor2). A re-examination of other similarly sequenced, archival virus stocks revealed induced proviruses of Haloferax volcanii, Haloferax gibbonsii and Haloarcula hispanica, three of which were pleolipoviruses. One provirus (Halfvol2) of Hfx. volcanii showed little similarity (BLASTn) to known viruses and probably represents a novel virus group. The attP sequences of many pleolipoproviruses were found to be embedded in a newly detected coding sequence, split in the provirus state, that spans between genes for integrase and a downstream CxxC-motif protein. This gene might play an important role in regulation of the temperate state.
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Pfeiffer F, Losensky G, Marchfelder A, Habermann B, Dyall‐Smith M. Whole-genome comparison between the type strain of Halobacterium salinarum (DSM 3754 T ) and the laboratory strains R1 and NRC-1. Microbiologyopen 2020; 9:e974. [PMID: 31797576 PMCID: PMC7002104 DOI: 10.1002/mbo3.974] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 11/08/2019] [Accepted: 11/09/2019] [Indexed: 01/04/2023] Open
Abstract
Halobacterium salinarum is an extremely halophilic archaeon that is widely distributed in hypersaline environments and was originally isolated as a spoilage organism of salted fish and hides. The type strain 91-R6 (DSM 3754T ) has seldom been studied and its genome sequence has only recently been determined by our group. The exact relationship between the type strain and two widely used model strains, NRC-1 and R1, has not been described before. The genome of Hbt. salinarum strain 91-R6 consists of a chromosome (2.17 Mb) and two large plasmids (148 and 102 kb, with 39,230 bp being duplicated). Cytosine residues are methylated (m4 C) within CTAG motifs. The genomes of type and laboratory strains are closely related, their chromosomes sharing average nucleotide identity (ANIb) values of 98% and in silico DNA-DNA hybridization (DDH) values of 95%. The chromosomes are completely colinear, do not show genome rearrangement, and matching segments show <1% sequence difference. Among the strain-specific sequences are three large chromosomal replacement regions (>10 kb). The well-studied AT-rich island (61 kb) of the laboratory strains is replaced by a distinct AT-rich sequence (47 kb) in 91-R6. Another large replacement (91-R6: 78 kb, R1: 44 kb) codes for distinct homologs of proteins involved in motility and N-glycosylation. Most (107 kb) of plasmid pHSAL1 (91-R6) is very closely related to part of plasmid pHS3 (R1) and codes for essential genes (e.g. arginine-tRNA ligase and the pyrimidine biosynthesis enzyme aspartate carbamoyltransferase). Part of pHS3 (42.5 kb total) is closely related to the largest strain-specific sequence (164 kb) in the type strain chromosome. Genome sequencing unraveled the close relationship between the Hbt. salinarum type strain and two well-studied laboratory strains at the DNA and protein levels. Although an independent isolate, the type strain shows a remarkably low evolutionary difference to the laboratory strains.
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Affiliation(s)
- Friedhelm Pfeiffer
- Computational Biology GroupMax‐Planck‐Institute of BiochemistryMartinsriedGermany
| | - Gerald Losensky
- Microbiology and ArchaeaDepartment of BiologyTechnische Universität DarmstadtDarmstadtGermany
| | | | - Bianca Habermann
- Computational Biology GroupMax‐Planck‐Institute of BiochemistryMartinsriedGermany
- CNRSIBDM UMR 7288Aix Marseille UniversitéMarseilleFrance
| | - Mike Dyall‐Smith
- Computational Biology GroupMax‐Planck‐Institute of BiochemistryMartinsriedGermany
- Veterinary BiosciencesFaculty of Veterinary and Agricultural SciencesUniversity of MelbourneParkvilleVic.Australia
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Dyall-Smith M, Palm P, Wanner G, Witte A, Oesterhelt D, Pfeiffer F. Halobacterium salinarum virus ChaoS9, a Novel Halovirus Related to PhiH1 and PhiCh1. Genes (Basel) 2019; 10:E194. [PMID: 30832293 DOI: 10.3390/genes10030194] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 02/21/2019] [Accepted: 02/25/2019] [Indexed: 11/17/2022] Open
Abstract
The unexpected lysis of a large culture of Halobacterium salinarum strain S9 was found to be caused by a novel myovirus, designated ChaoS9. Virus purification from the culture lysate revealed a homogeneous population of caudovirus-like particles. The viral genome is linear, dsDNA that is partially redundant and circularly permuted, has a unit length of 55,145 nt, a G + C% of 65.3, and has 85 predicted coding sequences (CDS) and one tRNA (Arg) gene. The left arm of the genome (0–28 kbp) encodes proteins similar in sequence to those from known caudoviruses and was most similar to myohaloviruses phiCh1 (host: Natrialba magadii) and phiH1 (host: Hbt. salinarum). It carries a tail-fiber gene module similar to the invertible modules present in phiH1 and phiCh1. However, while the tail genes of ChaoS9 were similar to those of phiCh1 and phiH1, the Mcp of ChaoS9 was most similar (36% aa identity) to that of Haloarcula hispanica tailed virus 1 (HHTV-1). Provirus elements related to ChaoS9 showed most similarity to tail/assembly proteins but varied in their similarity with head/assembly proteins. The right arm (29–55 kbp) of ChaoS9 encoded proteins involved in DNA replication (ParA, RepH, and Orc1) but the other proteins showed little similarity to those from phiH1, phiCh1, or provirus elements, and most of them could not be assigned a function. ChaoS9 is probably best classified within the genus Myohalovirus, as it shares many characteristics with phiH1 (and phiCh1), including many similar proteins. However, the head/assembly gene region appears to have undergone a recombination event, and the inferred proteins are different to those of phiH1 and phiCh1, including the major capsid protein. This makes the taxonomic classification of ChaoS9 more ambiguous. We also report a revised genome sequence and annotation of Natrialba virus phiCh1.
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Dyall-Smith M, Pfeifer F, Witte A, Oesterhelt D, Pfeiffer F. Complete Genome Sequence of the Model Halovirus PhiH1 (ΦH1). Genes (Basel) 2018; 9:E493. [PMID: 30322017 DOI: 10.3390/genes9100493] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 10/05/2018] [Accepted: 10/08/2018] [Indexed: 11/17/2022] Open
Abstract
The halophilic myohalovirus Halobacterium virus phiH (ΦH) was first described in 1982 and was isolated from a spontaneously lysed culture of Halobacterium salinarum strain R1. Until 1994, it was used extensively as a model to study the molecular genetics of haloarchaea, but only parts of the viral genome were sequenced during this period. Using Sanger sequencing combined with high-coverage Illumina sequencing, the full genome sequence of the major variant (phiH1) of this halovirus has been determined. The dsDNA genome is 58,072 bp in length and carries 97 protein-coding genes. We have integrated this information with the previously described transcription mapping data. PhiH could be classified into Myoviridae Type1, Cluster 4 based on capsid assembly and structural proteins (VIRFAM). The closest relative was Natrialba virus phiCh1 (φCh1), which shared 63% nucleotide identity and displayed a high level of gene synteny. This close relationship was supported by phylogenetic tree reconstructions. The complete sequence of this historically important virus will allow its inclusion in studies of comparative genomics and virus diversity.
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Abstract
Plasmids PL6A and PL6B are both carried by the C23T strain of the square archaeon Haloquadratum walsbyi, and are closely related (76% nucleotide identity), circular, about 6 kb in size, and display the same gene synteny. They are unrelated to other known plasmids and all of the predicted proteins are cryptic in function. Here we describe two additional PL6-related plasmids, pBAJ9-6 and pLT53-7, each carried by distinct isolates of Haloquadratum walsbyi that were recovered from hypersaline waters in Australia. A third PL6-like plasmid, pLTMV-6, was assembled from metavirome data from Lake Tyrell, a salt-lake in Victoria, Australia. Comparison of all five plasmids revealed a distinct plasmid family with strong conservation of gene content and synteny, an average size of 6.2 kb (range 5.8-7.0 kb) and pairwise similarities between 61-79%. One protein (F3) was closely similar to a protein carried by betapleolipoviruses while another (R6) was similar to a predicted AAA-ATPase of His 1 halovirus (His1V_gp16). Plasmid pLT53-7 carried a gene for a FkbM family methyltransferase that was not present in any of the other plasmids. Comparative analysis of all PL6-like plasmids provided better resolution of conserved sequences and coding regions, confirmed the strong link to haloviruses, and showed that their sequences are highly conserved among examples from Haloquadratum isolates and metagenomic data that collectively cover geographically distant locations, indicating that these genetic elements are widespread.
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Affiliation(s)
- Mike Dyall-Smith
- Computational Biology Group, Max Planck Institute of Biochemistry, Martinsried, Germany.,Department of Veterinary Biosciences, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Friedhelm Pfeiffer
- Computational Biology Group, Max Planck Institute of Biochemistry, Martinsried, Germany
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Abstract
This research uses inteins, a type of mobile genetic element, to infer patterns of gene transfer within the Halobacteria. We surveyed 118 genomes representing 26 genera of Halobacteria for intein sequences. We then used the presence-absence profile, sequence similarity and phylogenies from the inteins recovered to explore how intein distribution can provide insight on the dynamics of gene flow between closely related and divergent organisms. We identified 24 proteins in the Halobacteria that have been invaded by inteins at some point in their evolutionary history, including two proteins not previously reported to contain an intein. Furthermore, the size of an intein is used as a heuristic for the phase of the intein's life cycle. Larger size inteins are assumed to be the canonical two domain inteins, consisting of self-splicing and homing endonuclease domains (HEN); smaller sizes are assumed to have lost the HEN domain. For many halobacterial groups the consensus phylogenetic signal derived from intein sequences is compatible with vertical inheritance or with a strong gene transfer bias creating these clusters. Regardless, the coexistence of intein-free and intein-containing alleles reveal ongoing transfer and loss of inteins within these groups. Inteins were frequently shared with other Euryarchaeota and among the Bacteria, with members of the Cyanobacteria (Cyanothece, Anabaena), Bacteriodetes (Salinibacter), Betaproteobacteria (Delftia, Acidovorax), Firmicutes (Halanaerobium), Actinobacteria (Longispora), and Deinococcus-Thermus-group.
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Affiliation(s)
- Shannon M Soucy
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
| | - Matthew S Fullmer
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
| | - R Thane Papke
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
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Paula DP, Gleny A, Martha H, Patricia P, Susana S, Fabrizio Q, Gonzalo R, Pedro S, Diana A, Karem G, Carlos CO. Kinetics of arsenite removal by halobacteria from a highland Andean Chilean Salar. Aquat Biosyst 2013; 9:8. [PMID: 23547876 PMCID: PMC3616940 DOI: 10.1186/2046-9063-9-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 02/21/2013] [Indexed: 06/02/2023]
Abstract
BACKGROUND The purpose of this study was to identify arsenite-oxidizing halobacteria in samples obtained from Salar de Punta Negra, II Region of Chile. Seven bacterial isolates, numbered as isolates I to VII, grown in a culture medium with 100 ppm as NaAsO2 (As (III)) were tested. Bacterial growth kinetics and the percent of arsenite removal (PAR) were performed simultaneously with the detection of an arsenite oxidase enzyme through Dot Blot analysis. RESULTS An arsenite oxidase enzyme was detected in all isolates, expressed constitutively after 10 generations grown in the absence of As (III). Bacterial growth kinetics and corresponding PAR values showed significant fluctuations over time. PARs close to 100% were shown by isolates V, VI, and VII, at different times of the bacterial growth phase; while isolate II showed PAR values around 40%, remaining constant over time. CONCLUSION Halobacteria from Salar de Punta Negra showed promising properties as arsenite removers under control conditions, incubation time being a critical parameter.
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Affiliation(s)
- Díaz-Palma Paula
- Departamento de Química, Facultad de Ciencias, Universidad Católica del Norte, P.O.1280, Antofagasta, Chile
- Advanced Mining Technology Center, AMTC, Universidad de Chile, Tupper 2007, Santiago, Chile
| | - Alfaro Gleny
- Departamento de Química, Facultad de Ciencias, Universidad Católica del Norte, P.O.1280, Antofagasta, Chile
| | - Hengst Martha
- Laboratorio de Complejidad Microbiana y Ecología Funcional, Facultad de Recursos del Mar & Centro de BioInnovación de Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
| | - Pozo Patricia
- Departamento de Química, Facultad de Ciencias, Universidad Católica del Norte, P.O.1280, Antofagasta, Chile
| | - Stegen Susana
- Departamento de Química, Facultad de Ciencias, Universidad Católica del Norte, P.O.1280, Antofagasta, Chile
| | - Queirolo Fabrizio
- Departamento de Química, Facultad de Ciencias, Universidad Católica del Norte, P.O.1280, Antofagasta, Chile
| | - Rojo Gonzalo
- Departamento de Química, Facultad de Ciencias, Universidad Católica del Norte, P.O.1280, Antofagasta, Chile
| | - Silva Pedro
- Departamento de Química, Facultad de Ciencias, Universidad Católica del Norte, P.O.1280, Antofagasta, Chile
| | - Arias Diana
- Departamento de Química, Facultad de Ciencias, Universidad Católica del Norte, P.O.1280, Antofagasta, Chile
| | - Gallardo Karem
- Departamento de Química, Facultad de Ciencias, Universidad Católica del Norte, P.O.1280, Antofagasta, Chile
| | - Contreras-Ortega Carlos
- Departamento de Química, Facultad de Ciencias, Universidad Católica del Norte, P.O.1280, Antofagasta, Chile
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Spudich EN, Zhang W, Alam M, Spudich JL. Constitutive signaling by the phototaxis receptor sensory rhodopsin II from disruption of its protonated Schiff base-Asp-73 interhelical salt bridge. Proc Natl Acad Sci U S A 1997; 94:4960-5. [PMID: 9144172 PMCID: PMC24613 DOI: 10.1073/pnas.94.10.4960] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/1997] [Accepted: 03/17/1997] [Indexed: 02/04/2023] Open
Abstract
Sensory rhodopsin II (SRII) is a repellent phototaxis receptor in the archaeon Halobacterium salinarum, similar to visual pigments in its seven-helix structure and linkage of retinal to the protein by a protonated Schiff base in helix G. Asp-73 in helix C is shown by spectroscopic analysis to be a counterion to the protonated Schiff base in the unphotolyzed SRII and to be the proton acceptor from the Schiff base during photoconversion to the receptor signaling state. Coexpression of the genes encoding mutated SRII with Asn substituted for Asp-73 (D73N) and the SRII transducer HtrII in H. salinarum cells results in a 3-fold higher swimming reversal frequency accompanied by demethylation of HtrII in the dark, showing that D73N SRII produces repellent signals in its unphotostimulated state. Analogous constitutive signaling has been shown to be produced by the similar neutral residue substitution of the Schiff base counterion and proton acceptor Glu-113 in human rod rhodopsin. The interpretation for both seven-helix receptors is that light activation of the wild-type protein is caused primarily by photoisomerization-induced transfer of the Schiff base proton on helix G to its primary carboxylate counterion on helix C. Therefore receptor activation by helix C-G salt-bridge disruption in the photoactive site is a general mechanism in retinylidene proteins spanning the vast evolutionary distance between archaea and humans.
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Affiliation(s)
- E N Spudich
- Department of Microbiology and Molecular Genetics, University of Texas Medical School, Houston, TX 77030, USA
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Lewis A, Spoonhower J, Bogomolni RA, Lozier RH, Stoeckenius W. Tunable laser resonance raman spectroscopy of bacteriorhodopsin. Proc Natl Acad Sci U S A 1974; 71:4462-6. [PMID: 4530995 PMCID: PMC433906 DOI: 10.1073/pnas.71.11.4462] [Citation(s) in RCA: 280] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Bacteriorhodopsin is a rhodopsin-like protein found in the cell membrane of Halobacterium halobium. It shows an absorption maximum at 570 nm and, in the light, undergoes cyclic spectral changes which include a relatively long-lived complex absorbing maximally at 412 nm. Excitation profiles have been obtained with several laser frequencies for two vibrations in the resonance Raman spectrum of bacteriorhodopsin. The results show that the Schiff base retinylidene lysine linkage is protonated in the 570 nm complex and that in the 412 nm complex it is unprotonated. The 412 nm complex must be present at appreciable concentrations when bacteriorhodopsin is exposed to high-energy argon ion laser light of the Raman spectrophotometer at room temperature. We conclude that the observed C=N stretch at 1622 cm(-1) in the room temperature spectra, which in an earlier study by Mendelsohn was interpreted as evidence for an unprotonated linkage in bacteriorhodopsin, results from the presence of the 412 nm complex.
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Abstract
Halobacterium halobium cells grown under semi-anaerobic conditions convert part of their cell membrane into "purple membrane" which contains a rhodopsin-like protein, bacteriorhodopsin. Under anaerobic conditions in the dark the ATP content of such cells decreases sharply. Either light or oxygen restores the ATP content to the original level. The light effect is mediated by the purple membrane. Inhibitors of the respiratory chain abolish the oxygen response but do not affect the light response. Uncouplers, which function as proton translocators, abolish the light response. These results indicate that the purple membrane functions as a lightdriven proton pump and the cells use the resulting chemiosmotic gradient for ATP synthesis.
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