Abstract
Ancestral coatomer element 1 (ACE1) proteins assemble latticework coats for COPII vesicles and the nuclear pore complex. The ACE1 protein Sec31 and Sec13 make a 2:2 tetramer that forms the edge element of the COPII outer coat. In this study, we report that the COPII accessory protein Sec16 also contains an ACE1. The 165-kD crystal structure of the central domain of Sec16 in complex with Sec13 was solved at 2.7-A resolution. Sec16 and Sec13 also make a 2:2 tetramer, another edge element for the COPII system. Domain swapping at the ACE1-ACE1 interface is observed both in the prior structure of Sec13-Sec31 and in Sec13-Sec16. A Sec31 mutant in which domain swapping is prevented adopts an unprecedented laminated structure, solved at 2.8-A resolution. Our in vivo data suggest that the ACE1 element of Sec31 can functionally replace the ACE1 element of Sec16. Our data support Sec16 as a scaffold for the COPII system and a template for the Sec13-Sec31 coat.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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COP-Coated Vesicles / chemistry*
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COP-Coated Vesicles / metabolism*
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DNA-Binding Proteins / chemistry
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DNA-Binding Proteins / metabolism
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Endoplasmic Reticulum / chemistry
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Endoplasmic Reticulum / metabolism
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Membrane Proteins / chemistry*
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Membrane Proteins / genetics
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Membrane Proteins / metabolism
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Models, Molecular
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Mutation
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Nuclear Pore Complex Proteins / chemistry*
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Nuclear Pore Complex Proteins / genetics
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Nuclear Pore Complex Proteins / metabolism
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Protein Structure, Secondary
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Saccharomyces cerevisiae Proteins / chemistry*
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism
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Transcription Factors / chemistry
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Transcription Factors / metabolism
Substances
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CUP2 protein, S cerevisiae
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DNA-Binding Proteins
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Membrane Proteins
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Nuclear Pore Complex Proteins
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SEC13 protein, S cerevisiae
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SEC16 protein, S cerevisiae
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Saccharomyces cerevisiae Proteins
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Transcription Factors