Practical Guide to Homology Modeling: Difference between revisions
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== What Is A Homology Model? == | == What Is A Homology Model? == | ||
{{Template:Homology_Modeling_Intro}} | {{Template:Homology_Modeling_Intro}} | ||
== Rationale for homology modeling == | |||
The science of predicting the structure of a protein from its sequence, using theory, is generally unsuccessful, despite decades of work by some very bright people, and real progress having been made (see [[Theoretical models]]). | |||
Structure is more conserved than sequence. This conclusion is supported by many examples of proteins that have similar structures, yet no discernable sequence identity. An example is the ftsZ cell division protein in bacteria which shares structure with mammalian tubulin despite only 12-15% sequence identity<ref>A 3D structure similarity search gives tubulin as one of the closest matches to ftsZ, with an RMSD (alpha carbons) of <2.6 Å.</ref>. The customary interpretation is that modern proteins with very similar structures have a common ancestor, and that their sequences diverged while maintaining the ancestral 3D structure. | |||
Thus, if the query sequence has significant identity with an empirically determined protein structure (the template), there is a very high probability that they have similar structures. Folding the query sequence identically to the template, guiding the registration by the sequence alignment, produces a homology model. | |||
== Do you need a homology model? == | == Do you need a homology model? == | ||