Sandbox Reserved 935: Difference between revisions
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==Structure== | ==Structure== | ||
BRI1 belongs to a subgroup of the plant receptor-like kinases (RLKs) which are transmembrane receptor kinases. Plants have large numbers of RLKs (e.g. in Arabidopsis about 2.5% of all annotated protein coding genes belong to RLKs, rice possesses a similar number of RLKs). RLKs typically possess an intracellular kinase domain, a transmembrane region, extracellular domain(s) and a signal peptide. RLKs have been divided into 45 subfamilies based on their extracellular domains. The extracellular domain of BRI1 contains several leucine-rich repeat domains and thereby belongs to leucine-rich repeat-receptor-like kinases (LRR-RKs) . LRR-RKs are by far the largest group of RLKs in Arabidopsis <ref name=Bojar2014 />. The BRI1 nucleotide binding site is located between the N- and C-lobes of the protein. | BRI1 belongs to a subgroup of the plant receptor-like kinases (RLKs) which are transmembrane receptor kinases. Plants have large numbers of RLKs (e.g. in Arabidopsis about 2.5% of all annotated protein coding genes belong to RLKs, rice possesses a similar number of RLKs) <ref name=Shiu2004>Shiu SH, Karlowski WM, Pan R, Tzeng YH, Mayer KFX & Li WH (2004) Comparative Analysis of the Receptor-like Kinase Family in Arabidopsis and Rice. The Plant Cell 16:1220-1234</ref>. RLKs typically possess an intracellular kinase domain, a transmembrane region, extracellular domain(s) and a signal peptide. RLKs have been divided into 45 subfamilies based on their extracellular domains. The extracellular domain of BRI1 contains several leucine-rich repeat domains and thereby belongs to leucine-rich repeat-receptor-like kinases (LRR-RKs) . LRR-RKs are by far the largest group of RLKs in Arabidopsis <ref name=Bojar2014 />. The BRI1 nucleotide binding site is located between the N- and C-lobes of the protein. | ||
The kinase domain <scene name='57/579705/Nucleotide_binding_pocket/16'>nucleotide binding pocket</scene> adopts an active conformation with a salt-bridge between Lysine-911 and Glutamate-927 <ref name=Bojar2014 />. There is also a hydrogen bond between Glutamate-927 and Tyrosine-956. This tyrosine residue is a gatekeeper determining the size of the nucleotide binding pocket. Comparison with other plant receptor-like kinases suggests this hydrogen bond interaction and salt-bridge are important for the activation, because they are holding the binding pocket in its active conformation. | The kinase domain <scene name='57/579705/Nucleotide_binding_pocket/16'>nucleotide binding pocket</scene> adopts an active conformation with a salt-bridge between Lysine-911 and Glutamate-927 <ref name=Bojar2014 />. There is also a hydrogen bond between Glutamate-927 and Tyrosine-956. This tyrosine residue is a gatekeeper determining the size of the nucleotide binding pocket. Comparison with other plant receptor-like kinases suggests this hydrogen bond interaction and salt-bridge are important for the activation, because they are holding the binding pocket in its active conformation. | ||
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==Homologs== | ==Homologs== | ||
There are homologs for the kinase domain of BRI1 not only in plants but also in other eukaryotes <ref name=Bojar2014 />. Homologs in plants have similar domain structure in the whole protein, but in animals the other domains than kinase domain are different. The closest similarity to the kinase domain of BRI1 in ''Arabidopsis thaliana'' is interleukin-1 receptor-associated kinase 4 (IRAK4) in human and mouse. Similar kinase in ''Drosophila melanogaster'' is called Pelle-kinase. | There are homologs for the kinase domain of BRI1 not only in plants but also in other eukaryotes <ref name=Bojar2014 />. Homologs in plants have similar domain structure in the whole protein, but in animals the other domains than kinase domain are different. The closest similarity to the kinase domain of BRI1 in ''Arabidopsis thaliana'' is interleukin-1 receptor-associated kinase 4 (IRAK4) in human and mouse. Similar kinase in ''Drosophila melanogaster'' is called Pelle-kinase. Structural similarity between kinase domains of BRI1 and human IRAK4 is high and they both are dual-specificity kinases. It seems likely that the last common ancestor of Pelle/IRAK kinases and plant receptor kinases already had both serine-threonine and tyrosine activity and this feature has been preserved in both animals and plants <ref name=Bojar2014 />. | ||
[[Image:BRI1_phylogeny3.jpg|thumb|1200px|alt=Figure|Phylogeny of close relatives to BRI1. Based on amino acid sequences of kinase domain, ClustalW alignment and ML tree.]] | [[Image:BRI1_phylogeny3.jpg|thumb|1200px|alt=Figure|Phylogeny of close relatives to BRI1. Based on amino acid sequences of kinase domain, ClustalW alignment and ML tree.]] | ||
