Identification of functionally important acidic residues in transducin by group-specific labeling

Transducin (T), a GTP-binding protein involved in phototransduction of rod photoreceptor cells, is a heterotrimer arranged as two units, the a-subunit (Ta) and the bg-complex (Tbg). The role of the carboxyl groups in T was evaluated by labeling with N, N'-dicyclohexylcarbodiimide (DCCD) and 1-e...

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Autores principales:	KOSOY,ANA, MÖLLER,CAROLINA, PERDOMO,DEISY
Lenguaje:	English
Publicado:	Sociedad de Biología de Chile 2003
Materias:	Chemical modification G-protein-coupled signaling group-specific labeling transducin visual process
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602003000300010
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spelling	oai:scielo:S0716-976020030003000102004-08-17Identification of functionally important acidic residues in transducin by group-specific labelingKOSOY,ANAMÖLLER,CAROLINAPERDOMO,DEISY Chemical modification G-protein-coupled signaling group-specific labeling transducin visual process Transducin (T), a GTP-binding protein involved in phototransduction of rod photoreceptor cells, is a heterotrimer arranged as two units, the a-subunit (Ta) and the bg-complex (Tbg). The role of the carboxyl groups in T was evaluated by labeling with N, N'-dicyclohexylcarbodiimide (DCCD) and 1-ethyl 3-(3-dimethylaminopropyl) carbodiimide (EDC). Only a minor effect on the binding of b, g-imido guanosine 5'-triphosphate (GMPpNp) to T was observed in the presence of the hydrophobic carbodiimide, DCCD. Similarly, the GMPpNp binding activity of the reconstituted holoenzyme was not significantly affected when Ta was combined with DCCD-treated Tbg. However, the binding of guanine nucleotides to the reconstituted T was ~50% inhibited when DCCD-labeled Ta was incubated with Tbg. In contrast, treatment of T with the hydrophilic carbodiimide, EDC, completely impaired its GMPpNp-binding ability. EDC-modified T was incapable of interacting with illuminated rhodopsin, as determined by sedimentation experiments. However, rhodopsin only partially protected against the inactivation of T. Additionally, analyses of trypsin digestion patterns showed that fluoroaluminate was not capable of activating the EDC-labeled T sample. The function of the reconstituted holoenzyme was also disrupted when EDC-modified Ta was combined with Tbg, and when EDC-treated Tbg was incubated with Tainfo:eu-repo/semantics/openAccessSociedad de Biología de ChileBiological Research v.36 n.3-4 20032003-01-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602003000300010en10.4067/S0716-97602003000300010
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	Chemical modification G-protein-coupled signaling group-specific labeling transducin visual process
spellingShingle	Chemical modification G-protein-coupled signaling group-specific labeling transducin visual process KOSOY,ANA MÖLLER,CAROLINA PERDOMO,DEISY Identification of functionally important acidic residues in transducin by group-specific labeling
description	Transducin (T), a GTP-binding protein involved in phototransduction of rod photoreceptor cells, is a heterotrimer arranged as two units, the a-subunit (Ta) and the bg-complex (Tbg). The role of the carboxyl groups in T was evaluated by labeling with N, N'-dicyclohexylcarbodiimide (DCCD) and 1-ethyl 3-(3-dimethylaminopropyl) carbodiimide (EDC). Only a minor effect on the binding of b, g-imido guanosine 5'-triphosphate (GMPpNp) to T was observed in the presence of the hydrophobic carbodiimide, DCCD. Similarly, the GMPpNp binding activity of the reconstituted holoenzyme was not significantly affected when Ta was combined with DCCD-treated Tbg. However, the binding of guanine nucleotides to the reconstituted T was ~50% inhibited when DCCD-labeled Ta was incubated with Tbg. In contrast, treatment of T with the hydrophilic carbodiimide, EDC, completely impaired its GMPpNp-binding ability. EDC-modified T was incapable of interacting with illuminated rhodopsin, as determined by sedimentation experiments. However, rhodopsin only partially protected against the inactivation of T. Additionally, analyses of trypsin digestion patterns showed that fluoroaluminate was not capable of activating the EDC-labeled T sample. The function of the reconstituted holoenzyme was also disrupted when EDC-modified Ta was combined with Tbg, and when EDC-treated Tbg was incubated with Ta
author	KOSOY,ANA MÖLLER,CAROLINA PERDOMO,DEISY
author_facet	KOSOY,ANA MÖLLER,CAROLINA PERDOMO,DEISY
author_sort	KOSOY,ANA
title	Identification of functionally important acidic residues in transducin by group-specific labeling
title_short	Identification of functionally important acidic residues in transducin by group-specific labeling
title_full	Identification of functionally important acidic residues in transducin by group-specific labeling
title_fullStr	Identification of functionally important acidic residues in transducin by group-specific labeling
title_full_unstemmed	Identification of functionally important acidic residues in transducin by group-specific labeling
title_sort	identification of functionally important acidic residues in transducin by group-specific labeling
publisher	Sociedad de Biología de Chile
publishDate	2003
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602003000300010
work_keys_str_mv	AT kosoyana identificationoffunctionallyimportantacidicresiduesintransducinbygroupspecificlabeling AT mollercarolina identificationoffunctionallyimportantacidicresiduesintransducinbygroupspecificlabeling AT perdomodeisy identificationoffunctionallyimportantacidicresiduesintransducinbygroupspecificlabeling
_version_	1718441357280804864

Identification of functionally important acidic residues in transducin by group-specific labeling

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