3cwo
A beta/alpha-barrel built by the combination of fragments from different folds
Structural highlights
FunctionHIS6_THEMA IGPS catalyzes the conversion of PRFAR and glutamine to IGP, AICAR and glutamate. The HisF subunit catalyzes the cyclization activity that produces IGP and AICAR from PRFAR using the ammonia provided by the HisH subunit.[HAMAP-Rule:MF_01013] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCombinatorial assembly of protein domains plays an important role in the evolution of proteins. There is also evidence that protein domains have come together from stable subdomains. This concept of modular assembly could be used to construct new well folded proteins from stable protein fragments. Here, we report the construction of a chimeric protein from parts of a (betaalpha)(8)-barrel enzyme from histidine biosynthesis pathway (HisF) and a protein of the (betaalpha)(5)-flavodoxin-like fold (CheY) from Thermotoga maritima that share a high structural similarity. We expected this construct to fold into a full (betaalpha)(8)-barrel. Our results show that the chimeric protein is a stable monomer that unfolds with high cooperativity. Its three-dimensional structure, which was solved to 3.1 A resolution by x-ray crystallography, confirms a barrel-like fold in which the overall structures of the parent proteins are highly conserved. The structure further reveals a ninth strand in the barrel, which is formed by residues from the HisF C terminus and an attached tag. This strand invades between beta-strand 1 and 2 of the CheY part closing a gap in the structure that might be due to a suboptimal fit between the fragments. Thus, by a combination of parts from two different folds and a small arbitrary fragment, we created a well folded and stable protein. A beta alpha-barrel built by the combination of fragments from different folds.,Bharat TA, Eisenbeis S, Zeth K, Hocker B Proc Natl Acad Sci U S A. 2008 Jul 22;105(29):9942-7. Epub 2008 Jul 15. PMID:18632584[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References | ||||||||||||||||||||
