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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
4
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pubmed:dateCreated |
1994-11-2
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pubmed:abstractText |
Since the first crystal structure of an immunoglobulin revealed a modular architecture, the characteristic beta-sheet fold of the immunoglobulin domain has been found in many other proteins of diverse biological function. Here, a systematic comparison of 23 Ig domain structures with less than 25% pairwise residue identity was performed using automatic structural alignment and analysis of beta-sheet and loop topology. Sequence consensus patterns were identified for nine distinct families with at most marginal similarity to each other. The analysis reveals a common structural core of only four beta-strands (b, c, e and f), embedded in an antiparallel curled beta-sheet sandwich with a total of three to five additional strands (a, c', c'', d, g) and a characteristic intersheet angle. The variation in the position of the edge strands (a, c', c'', d and g) relative to the common core defines four different topological subtypes that correlate with the length of the intervening sequence between strands c and e, the most variable region in sequence. The switch of strand c' from one sheet to the other in seven-stranded domains appears to result from short c-e segments, rather than being a major structural discriminator. The high degree of structural flexibility outside the common core and the extreme variability of side-chain packing inside the core do not support a protein folding pathway common to all members of the structural class. Mutation rates of immunoglobulin-like domains in different proteins vary considerably. Disulfide bridges, thought to contribute to structural stability, are not necessarily invariant in number and location within a subclass.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
|
pubmed:chemical | |
pubmed:status |
MEDLINE
|
pubmed:month |
Sep
|
pubmed:issn |
0022-2836
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pubmed:author | |
pubmed:issnType |
Print
|
pubmed:day |
30
|
pubmed:volume |
242
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
|
pubmed:pagination |
309-20
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pubmed:dateRevised |
2005-11-16
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pubmed:meshHeading |
pubmed-meshheading:7932691-Amino Acid Sequence,
pubmed-meshheading:7932691-Animals,
pubmed-meshheading:7932691-Humans,
pubmed-meshheading:7932691-Immunoglobulins,
pubmed-meshheading:7932691-Molecular Sequence Data,
pubmed-meshheading:7932691-Protein Binding,
pubmed-meshheading:7932691-Protein Conformation,
pubmed-meshheading:7932691-Protein Folding
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pubmed:year |
1994
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pubmed:articleTitle |
The immunoglobulin fold. Structural classification, sequence patterns and common core.
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pubmed:affiliation |
EMBL, Heidelberg, Germany.
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pubmed:publicationType |
Journal Article,
Review
|