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What and Who
Multidomain protein evolution and orphans.
Arne Elofsson
Department of Biochemistry & Biophysics, Stockholm University
CBI Colloquium Series
AG 1, AG 2, AG 3, AG 4, AG 5, SWS, RG1, MMCI
Public Audience
English
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Date, Time and Location
Wednesday, 17 November 2010
17:00
60 Minutes
E2 1
001
Saarbrücken
Abstract
Multidomain protein evolution and orphans.
More than 70% of the proteins in the human proteome consist of multiple
domains and about 17% of the proteins contain repeated domains. We
have found that the evolution of most multi-domain proteins can be
explained by simple addition of single domains at the N or C-terminus.
However, one important exception to this rule exists, the evolution of
repeating domains.
The domain concept is a fundamental concept in our
understanding of proteins. It is assumed that a domain is “an
independently folding unit” as well as “evolutionary
independent”. More than 70% of the proteins in the human
proteome consist of multiple domains and about 17% of the
proteins contain repeated domains. In the human cells repeated
domains are essential for signaling and regulation and are
frequent among protein interaction hubs. Here, we will discuss
mechanisms involved in the evolution of domains and domain
architectures. Also, for large regions of many proteins, and even
entire proteins, no homology to known domains or to other
proteins can be detected. These sequences are often referred to as
orphans. However, it is believed that de novo creation of coding
sequences is rare in comparison to mechanisms such as domain
shuffling and gene duplication, hence most sequences should have
homologs in other genomes. Surprisingly, the large amount of
orphans is sustained in spite of a rapid increase of available
genomic sequences. From a careful analysis of orphan domains in different yeast species we have found indication that orphan domains are rarer than earlier reported but that they actually resemble normal proteins more. This is due to that earlier classifications often confused true orphan domains with rapidly evolving preferably disordered proteins.
More than 70% of the proteins in the human proteome consist of multiple
domains and about 17% of the proteins contain repeated domains. We
have found that the evolution of most multi-domain proteins can be
explained by simple addition of single domains at the N or C-terminus.
However, one important exception to this rule exists, the evolution of
repeating domains.
The domain concept is a fundamental concept in our
understanding of proteins. It is assumed that a domain is “an
independently folding unit” as well as “evolutionary
independent”. More than 70% of the proteins in the human
proteome consist of multiple domains and about 17% of the
proteins contain repeated domains. In the human cells repeated
domains are essential for signaling and regulation and are
frequent among protein interaction hubs. Here, we will discuss
mechanisms involved in the evolution of domains and domain
architectures. Also, for large regions of many proteins, and even
entire proteins, no homology to known domains or to other
proteins can be detected. These sequences are often referred to as
orphans. However, it is believed that de novo creation of coding
sequences is rare in comparison to mechanisms such as domain
shuffling and gene duplication, hence most sequences should have
homologs in other genomes. Surprisingly, the large amount of
orphans is sustained in spite of a rapid increase of available
genomic sequences. From a careful analysis of orphan domains in different yeast species we have found indication that orphan domains are rarer than earlier reported but that they actually resemble normal proteins more. This is due to that earlier classifications often confused true orphan domains with rapidly evolving preferably disordered proteins.
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Ruth Schneppen-Christmann, 11/11/2010 14:14 -- Created document.