Schiff base deprotonation and structural changes in a mouse UVsensitive cone visual pigment revealed by FTIR spectroscopy at 77 K.
Saved in:
| Title: | Schiff base deprotonation and structural changes in a mouse UVsensitive cone visual pigment revealed by FTIR spectroscopy at 77 K. |
|---|---|
| Authors: | Mizuno, Yosuke1, Arai, Sora1, Katayama, Kota1,2 katayama.kota@nitech.ac.jp, Kandori, Hideki1,2 kandori@nitech.ac.jp |
| Source: | Biophysics & Physicobiology. 2025, Vol. 22 Issue 4, p95;1-95;13. 13p. |
| Subjects: | Visual pigments, Hydrogen bonding, Chemical reactions, Fourier transform infrared spectroscopy |
| Abstract: | UV-sensitive cone visual pigments are widespread among vertebrates, including birds, fish, and rodents such as mice, and play essential roles in non-primate vision. Unlike visible-light pigments, which contain a protonated retinal Schiff base and absorb at 400-700 nm, UV pigments maintain a deprotonated Schiff base, but how this state is stabilized has remained unresolved. Here, we applied low-temperature FTIR spectroscopy to the mouse UV-sensitive cone visual pigment (MUV), capturing structural changes associated with Batho intermediate formation. Spectral features characteristic of a deprotonated Schiff base were observed in both the initial and Batho states. Importantly, analysis of the Glu113 mutant demonstrated that Glu113 is protonated under these condition. Combined with the analysis of proteinbound water signals, these results indicate that the hydroxyl group of Glu113 serves as a direct hydrogen-bond donor to the deprotonated Schiff base. Moreover, the Glu113 C=O stretching vibration appeared at an unusually low frequency, revealing the presence of an exceptionally strong hydrogen bond with its surrounding protein environment. Comparison with bovine rhodopsin and cone pigments further revealed that MUV binds fewer water molecules near the retinal. This reduction in hydration suggests that a more hydrophobic environment contributes to lowering the Schiff base pKa and stabilizing its deprotonated state. Sequence analyses across species support this view, highlighting conserved nonpolar residues in transmembrane helix 2 (TM2) that likely disrupt hydrogenbonding networks and promote UV sensitivity. Together, these findings establish MUV as a model for understanding how specific amino acid environments and hydration patterns enable UV vision in vertebrates. [ABSTRACT FROM AUTHOR] |
| Copyright of Biophysics & Physicobiology is the property of Biophysical Society of Japan General Incorporated Association (BSJ) and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Links: – Type: pdflink Text: Availability: 0 |
|---|---|
| Header | DbId: egs DbLabel: Engineering Source An: 192476525 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
| IllustrationInfo | |
| Items | – Name: Title Label: Title Group: Ti Data: Schiff base deprotonation and structural changes in a mouse UVsensitive cone visual pigment revealed by FTIR spectroscopy at 77 K. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Mizuno%2C+Yosuke%22">Mizuno, Yosuke</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Arai%2C+Sora%22">Arai, Sora</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Katayama%2C+Kota%22">Katayama, Kota</searchLink><relatesTo>1,2</relatesTo><i> katayama.kota@nitech.ac.jp</i><br /><searchLink fieldCode="AR" term="%22Kandori%2C+Hideki%22">Kandori, Hideki</searchLink><relatesTo>1,2</relatesTo><i> kandori@nitech.ac.jp</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Biophysics+%26+Physicobiology%22">Biophysics & Physicobiology</searchLink>. 2025, Vol. 22 Issue 4, p95;1-95;13. 13p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Visual+pigments%22">Visual pigments</searchLink><br /><searchLink fieldCode="DE" term="%22Hydrogen+bonding%22">Hydrogen bonding</searchLink><br /><searchLink fieldCode="DE" term="%22Chemical+reactions%22">Chemical reactions</searchLink><br /><searchLink fieldCode="DE" term="%22Fourier+transform+infrared+spectroscopy%22">Fourier transform infrared spectroscopy</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: UV-sensitive cone visual pigments are widespread among vertebrates, including birds, fish, and rodents such as mice, and play essential roles in non-primate vision. Unlike visible-light pigments, which contain a protonated retinal Schiff base and absorb at 400-700 nm, UV pigments maintain a deprotonated Schiff base, but how this state is stabilized has remained unresolved. Here, we applied low-temperature FTIR spectroscopy to the mouse UV-sensitive cone visual pigment (MUV), capturing structural changes associated with Batho intermediate formation. Spectral features characteristic of a deprotonated Schiff base were observed in both the initial and Batho states. Importantly, analysis of the Glu113 mutant demonstrated that Glu113 is protonated under these condition. Combined with the analysis of proteinbound water signals, these results indicate that the hydroxyl group of Glu113 serves as a direct hydrogen-bond donor to the deprotonated Schiff base. Moreover, the Glu113 C=O stretching vibration appeared at an unusually low frequency, revealing the presence of an exceptionally strong hydrogen bond with its surrounding protein environment. Comparison with bovine rhodopsin and cone pigments further revealed that MUV binds fewer water molecules near the retinal. This reduction in hydration suggests that a more hydrophobic environment contributes to lowering the Schiff base pKa and stabilizing its deprotonated state. Sequence analyses across species support this view, highlighting conserved nonpolar residues in transmembrane helix 2 (TM2) that likely disrupt hydrogenbonding networks and promote UV sensitivity. Together, these findings establish MUV as a model for understanding how specific amino acid environments and hydration patterns enable UV vision in vertebrates. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Biophysics & Physicobiology is the property of Biophysical Society of Japan General Incorporated Association (BSJ) and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
| PLink | https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=egs&AN=192476525 |
| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.2142/biophysico.bppb-v22.0030 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 13 StartPage: 95;1 Subjects: – SubjectFull: Visual pigments Type: general – SubjectFull: Hydrogen bonding Type: general – SubjectFull: Chemical reactions Type: general – SubjectFull: Fourier transform infrared spectroscopy Type: general Titles: – TitleFull: Schiff base deprotonation and structural changes in a mouse UVsensitive cone visual pigment revealed by FTIR spectroscopy at 77 K. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Mizuno, Yosuke – PersonEntity: Name: NameFull: Arai, Sora – PersonEntity: Name: NameFull: Katayama, Kota – PersonEntity: Name: NameFull: Kandori, Hideki IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 10 Text: 2025 Type: published Y: 2025 Identifiers: – Type: issn-print Value: 21894779 Numbering: – Type: volume Value: 22 – Type: issue Value: 4 Titles: – TitleFull: Biophysics & Physicobiology Type: main |
| ResultId | 1 |
