Type I and type II rhodopsins share several structural features including a G protein-coupled receptor fold and a highly conserved active-site Lys residue in the seventh transmembrane segment of the protein. However, the two families lack significant sequence similarity that would indicate common ancestry. Consequently, the rhodopsin fold and conserved Lys are widely thought to have arisen from functional constraints during convergent evolution. To test for the existence of such a constraint, we asked whether it were possible to relocate the highly conserved Lys296 in the visual pigment bovine rhodopsin. We show here that the Lys can be moved to three other locations in the protein while maintaining the ability to form a pigment with 11-cis-retinal and activate the G protein transducin in a light-dependent manner. These results contradict the convergent hypothesis and support the homology of type I and type II rhodopsins by divergent evolution from a common ancestral protein.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3746867 | PMC |
| http://dx.doi.org/10.1073/pnas.1306826110 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Transformers for Neuroimage Segmentation: Scoping Review.
J Med Internet Res
January 2025
Department of Computer Science and Software Engineering, United Arab Emirates University, Al Ain, United Arab Emirates.
Background: Neuroimaging segmentation is increasingly important for diagnosing and planning treatments for neurological diseases. Manual segmentation is time-consuming, apart from being prone to human error and variability. Transformers are a promising deep learning approach for automated medical image segmentation.
View Article and Find Full Text PDFEffectiveness of Different Intervention Modes in Lifestyle Intervention for the Prevention of Type 2 Diabetes and the Reversion to Normoglycemia in Adults With Prediabetes: Systematic Review and Meta-Analysis of Randomized Controlled Trials.
J Med Internet Res
January 2025
School of Population Medicine and Public Health, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
Background: Lifestyle interventions have been acknowledged as effective strategies for preventing type 2 diabetes mellitus (T2DM). However, the accessibility of conventional face-to-face interventions is often limited. Digital health intervention has been suggested as a potential solution to overcome the limitation.
View Article and Find Full Text PDFBackground And Aim: There is paucity of data about the prevalence of cirrhosis and portal hypertension in the US general population.
Methods: We used National Health and Nutrition Examination Surveys (NHANES 2017-2020) to estimate the prevalence of cirrhosis and clinically significant (CS)-portal hypertension in alcoholic liver disease (ALD), MetALD, viral hepatitis (VH) to include chronic hepatitis B (CHB) and chronic hepatitis C (CHC), and metabolic dysfunction-associated steatotic liver disease (MASLD). Cirrhosis was evaluated using liver stiffness measurement (LSM) by transient elastography or FIB-4 score; CS-portal hypertension was defined via LSM and platelet count or the use of non-selective beta-blockers in the presence of cirrhosis.
Nanoparticle encapsulation enables systemic IGF-Trap delivery to inhibit intra-cerebral glioma growth.
Neuro Oncol
January 2025
Department of Medicine, Division of Experimental Medicine, McGill University.
Background: Glioblastoma is an aggressive brain cancer with a 5-year survival rate of 5-10%. Current therapeutic options are limited, due in part to drug exclusion by the blood-brain barrier, restricting access of targeted drugs to the tumor. The receptor for the type 1 insulin-like growth factor (IGF-1R) was identified as a therapeutic target in glioblastoma.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!