Altered Envelope Structure and Nanomechanical Properties of a C-Terminal Protease A-Deficient <i>Rhizobium leguminosarum</i>
(1) Background: Many factors can impact bacterial mechanical properties, which play an important role in survival and adaptation. This study characterizes the ultrastructural phenotype, elastic and viscoelastic properties of <i>Rhizobium leguminosarum</i> bv. <i>viciae</i> 38...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2020-09-01
|
| Series: | Microorganisms |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-2607/8/9/1421 |
| _version_ | 1797553583721283584 |
|---|---|
| author | Dong Jun Ubong Idem Tanya E. S. Dahms |
| author_facet | Dong Jun Ubong Idem Tanya E. S. Dahms |
| author_sort | Dong Jun |
| collection | DOAJ |
| description | (1) Background: Many factors can impact bacterial mechanical properties, which play an important role in survival and adaptation. This study characterizes the ultrastructural phenotype, elastic and viscoelastic properties of <i>Rhizobium leguminosarum</i> bv. <i>viciae</i> 3841 and the C-terminal protease A (<i>ctpA</i>) null mutant strain predicted to have a compromised cell envelope; (2) Methods: To probe the cell envelope, we used transmission electron microscopy (TEM), high performance liquid chromatography (HPLC), mass spectrometry (MS), atomic force microscopy (AFM) force spectroscopy, and time-dependent AFM creep deformation; (3) Results: TEM images show a compromised and often detached outer membrane for the <i>ctpA</i> mutant. Muropeptide characterization by HPLC and MS showed an increase in peptidoglycan dimeric peptide (GlcNAc-MurNAc-Ala-Glu-meso-DAP-Ala-meso-DAP-Glu-Ala-MurNAc-GlcNAc) for the <i>ctpA</i> mutant, indicative of increased crosslinking. The <i>ctpA</i> mutant had significantly larger spring constants than wild type under all hydrated conditions, attributable to more highly crosslinked peptidoglycan. Time-dependent AFM creep deformation for both the wild type and <i>ctpA</i> mutant was indicative of a viscoelastic cell envelope, with best fit to the four-element Burgers model and generating values for viscoelastic parameters k<sub>1</sub>, k<sub>2</sub>, η<sub>1</sub>, and η<sub>2</sub>; (4) Conclusions: The viscoelastic response of the <i>ctpA</i> mutant is consistent with both its compromised outer membrane (TEM) and fortified peptidoglycan layer (HPLC/MS). |
| first_indexed | 2024-03-10T16:18:33Z |
| format | Article |
| id | doaj.art-640d7d24e80e4327a34e1e9661714d52 |
| institution | Directory Open Access Journal |
| issn | 2076-2607 |
| language | English |
| last_indexed | 2024-03-10T16:18:33Z |
| publishDate | 2020-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Microorganisms |
| spelling | doaj.art-640d7d24e80e4327a34e1e9661714d522023-11-20T13:52:34ZengMDPI AGMicroorganisms2076-26072020-09-0189142110.3390/microorganisms8091421Altered Envelope Structure and Nanomechanical Properties of a C-Terminal Protease A-Deficient <i>Rhizobium leguminosarum</i>Dong Jun0Ubong Idem1Tanya E. S. Dahms2Department of Chemistry and Biochemistry, University of Regina, Regina, SK S4S 0A2, CanadaDepartment of Chemistry and Biochemistry, University of Regina, Regina, SK S4S 0A2, CanadaDepartment of Chemistry and Biochemistry, University of Regina, Regina, SK S4S 0A2, Canada(1) Background: Many factors can impact bacterial mechanical properties, which play an important role in survival and adaptation. This study characterizes the ultrastructural phenotype, elastic and viscoelastic properties of <i>Rhizobium leguminosarum</i> bv. <i>viciae</i> 3841 and the C-terminal protease A (<i>ctpA</i>) null mutant strain predicted to have a compromised cell envelope; (2) Methods: To probe the cell envelope, we used transmission electron microscopy (TEM), high performance liquid chromatography (HPLC), mass spectrometry (MS), atomic force microscopy (AFM) force spectroscopy, and time-dependent AFM creep deformation; (3) Results: TEM images show a compromised and often detached outer membrane for the <i>ctpA</i> mutant. Muropeptide characterization by HPLC and MS showed an increase in peptidoglycan dimeric peptide (GlcNAc-MurNAc-Ala-Glu-meso-DAP-Ala-meso-DAP-Glu-Ala-MurNAc-GlcNAc) for the <i>ctpA</i> mutant, indicative of increased crosslinking. The <i>ctpA</i> mutant had significantly larger spring constants than wild type under all hydrated conditions, attributable to more highly crosslinked peptidoglycan. Time-dependent AFM creep deformation for both the wild type and <i>ctpA</i> mutant was indicative of a viscoelastic cell envelope, with best fit to the four-element Burgers model and generating values for viscoelastic parameters k<sub>1</sub>, k<sub>2</sub>, η<sub>1</sub>, and η<sub>2</sub>; (4) Conclusions: The viscoelastic response of the <i>ctpA</i> mutant is consistent with both its compromised outer membrane (TEM) and fortified peptidoglycan layer (HPLC/MS).https://www.mdpi.com/2076-2607/8/9/1421atomic force microscopycell envelopeC-terminal proteaseforce spectroscopy<i>Rhizobium leguminosarum</i>viscoelasticity |
| spellingShingle | Dong Jun Ubong Idem Tanya E. S. Dahms Altered Envelope Structure and Nanomechanical Properties of a C-Terminal Protease A-Deficient <i>Rhizobium leguminosarum</i> Microorganisms atomic force microscopy cell envelope C-terminal protease force spectroscopy <i>Rhizobium leguminosarum</i> viscoelasticity |
| title | Altered Envelope Structure and Nanomechanical Properties of a C-Terminal Protease A-Deficient <i>Rhizobium leguminosarum</i> |
| title_full | Altered Envelope Structure and Nanomechanical Properties of a C-Terminal Protease A-Deficient <i>Rhizobium leguminosarum</i> |
| title_fullStr | Altered Envelope Structure and Nanomechanical Properties of a C-Terminal Protease A-Deficient <i>Rhizobium leguminosarum</i> |
| title_full_unstemmed | Altered Envelope Structure and Nanomechanical Properties of a C-Terminal Protease A-Deficient <i>Rhizobium leguminosarum</i> |
| title_short | Altered Envelope Structure and Nanomechanical Properties of a C-Terminal Protease A-Deficient <i>Rhizobium leguminosarum</i> |
| title_sort | altered envelope structure and nanomechanical properties of a c terminal protease a deficient i rhizobium leguminosarum i |
| topic | atomic force microscopy cell envelope C-terminal protease force spectroscopy <i>Rhizobium leguminosarum</i> viscoelasticity |
| url | https://www.mdpi.com/2076-2607/8/9/1421 |
| work_keys_str_mv | AT dongjun alteredenvelopestructureandnanomechanicalpropertiesofacterminalproteaseadeficientirhizobiumleguminosarumi AT ubongidem alteredenvelopestructureandnanomechanicalpropertiesofacterminalproteaseadeficientirhizobiumleguminosarumi AT tanyaesdahms alteredenvelopestructureandnanomechanicalpropertiesofacterminalproteaseadeficientirhizobiumleguminosarumi |