Caspase-3/Sandbox: Difference between revisions
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==Structure & Function== | ==Structure & Function== | ||
===Structure=== | ===Structure=== | ||
Procaspase-3, unlike initiator procaspases, is a stable dimer with little enzymatic activity. Procaspase-3 contains a tri-aspartate ‘safety-catch’ (Asp179–Asp181) in the intersubunit linker to remain nonfunctional. During the process of activation, this linker undergoes a pH-dependent conformational change, exposing Asp175 for cleavage. This leads to the formation of a heterotetramer (Walters, 2011). The heterotetramer consists of two anti-parallel arranged heterodimers, each one formed by a 17 kDa (p17) and a 12 kDa (p12) subunit (http://www.uniprot.org/uniprot/P42574). | Procaspase-3, unlike initiator procaspases, is a stable dimer with little enzymatic activity. Procaspase-3 contains a tri-aspartate ‘safety-catch’ (Asp179–Asp181) in the intersubunit linker to remain nonfunctional. During the process of activation, this linker undergoes a pH-dependent conformational change, exposing Asp175 for cleavage. This leads to the formation of a heterotetramer (Walters, 2011). The heterotetramer consists of two anti-parallel arranged heterodimers, each one formed by a 17 kDa (p17) and a 12 kDa (p12) subunit (http://www.uniprot.org/uniprot/P42574). | ||
Caspase-3 chains are classified as alpha/beta, with one chain containing a 3-layer(aba) sandwich with Rossmann fold topology and another chain containing a 2-layer sandwich with alpha-beta plaits. | Caspase-3 consists of a twisted, mostly parallel beta-sheet sandwiched between two layers of alpha-helices. The chains are classified as alpha/beta, with one chain containing a 3-layer(aba) sandwich with Rossmann fold topology and another chain containing a 2-layer sandwich with alpha-beta plaits(Fuentes-Prior and Salvesen, 2004). | ||
[[Image:Rossman fold.png|300px|left]] | |||
[[Image:Caspase-3 topology.png|400px|center]] | |||
====Salt Bridge==== | ====Salt Bridge==== | ||