Beta sheet: Difference between revisions
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In a beta sheet, neighboring strands can either have a parallel or an antiparallel orientation, resulting in different hydrogen bonding pattern. The strands, if part of the same subunit, will all be connected as part of a single polypeptide. The parallel or antiparallel orientations and how strands are connected in their primary sequence is shown in topology ; these are useful to compare different protein folds. One example of such a beta sheet topology is the so-called greek key - an all-antiparallel sheet with four strands. | In a beta sheet, neighboring strands can either have a parallel or an antiparallel orientation, resulting in different hydrogen bonding pattern. The strands, if part of the same subunit, will all be connected as part of a single polypeptide. The parallel or antiparallel orientations and how strands are connected in their primary sequence is shown in topology ; these are useful to compare different protein folds. One example of such a beta sheet topology is the so-called greek key - an all-antiparallel sheet with four strands. | ||
[[Image:251px-Anthrax toxin protein key motif.svg.png]] | [[Image:251px-Anthrax toxin protein key motif.svg.png]] | ||
Some topologies occur very often while others have not yet been observed. There are some rules of thumb about preferred topologies. <ref>DOI: 10.1002/pro.3285</ref> | |||
==Types of proteins and folds that contain sheets== | ==Types of proteins and folds that contain sheets== | ||
===Beta sheets in soluble (globular) proteins=== | ===Beta sheets in soluble (globular) proteins=== | ||