Comparative analysis of cone and rod transducins using chimeric Gα subunits

Kota N Gopalakrishna; Kimberly K Boyd; Nikolai O Artemyev

doi:10.1021/bi3000935

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Comparative analysis of cone and rod transducins using chimeric Gα subunits

Journal article

Open access

Peer reviewed

Comparative analysis of cone and rod transducins using chimeric Gα subunits

Kota N Gopalakrishna, Kimberly K Boyd and Nikolai O Artemyev

Biochemistry (Easton), Vol.51(8), pp.1617-1624

02/28/2012

DOI: 10.1021/bi3000935

PMCID: PMC3291952

PMID: 22324825

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https://www.ncbi.nlm.nih.gov/pmc/articles/3291952View

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Abstract

The molecular nature of transducin-α subunits (Gα(t)) may contribute to the distinct physiology of cone and rod photoreceptors. Biochemical properties of mammalian cone Gα(t2) subunits and their differences with rod Gα(t1) are largely unknown. Here, we examined properties of chimeric Gα(t2) in comparison with its rod counterpart. The key biochemical difference between the rod- and cone-like Gα(t) was ~10-fold higher intrinsic nucleotide exchange on the chimeric Gα(t2). Presented mutational analysis suggests that weaker interdomain interactions between the GTPase (Ras-like) domain and the helical domain in Gα(t2) are in part responsible for its increased spontaneous nucleotide exchange. However, the rates of R*-dependent nucleotide exchange of chimeric Gα(t2) and Gα(t1) were equivalent. Furthermore, chimeric Gα(t2) and Gα(t1) exhibited similar rates of intrinsic GTPase activity as well as similar acceleration of GTP hydrolysis by the RGS domain of RGS9. Our results suggest that the activation and inactivation properties of cone and rod Gα(t) subunits in an in vitro reconstituted system are comparable.

GTP Phosphohydrolases - chemistry

Animals

GTP Phosphohydrolases - metabolism

Protein Structure, Secondary

Cattle

Cells, Cultured

Transducin - metabolism

Retinal Rod Photoreceptor Cells - metabolism

Retinal Cone Photoreceptor Cells - metabolism

Transducin - chemistry

Details

Title: Subtitle: Comparative analysis of cone and rod transducins using chimeric Gα subunits
Creators: Kota N Gopalakrishna - Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242, United States
Kimberly K Boyd
Nikolai O Artemyev
Resource Type: Journal article
Publication Details: Biochemistry (Easton), Vol.51(8), pp.1617-1624
DOI: 10.1021/bi3000935
PMID: 22324825
PMCID: PMC3291952
NLM abbreviation: Biochemistry
ISSN: 0006-2960
eISSN: 1520-4995
Publisher: United States
Grant note: EY-12682 / NEI NIH HHS R01 EY012682-13 / NEI NIH HHS R01 EY012682 / NEI NIH HHS
Language: English
Date published: 02/28/2012
Academic Unit: Molecular Physiology and Biophysics; Iowa Neuroscience Institute; Ophthalmology and Visual Sciences
Record Identifier: 9984025451202771

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