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          Institute: MPI für medizinische Forschung     Collection: Jahbruch 2014_archival     Display Documents

ID: 681438.0, MPI für medizinische Forschung / Jahbruch 2014_archival
Folding properties of cytosine monophosphate kinase from E. coli indicate stabilization through an additional insert in the NMP binding domain
Translation of Title:Folding properties of cytosine monophosphate kinase from E. coli indicate stabilization through an additional insert in the NMP binding domain
Authors:Beitlich, Thorsten; Lorenz, Thorsten; Reinstein, Jochen
Date of Publication (YYYY-MM-DD):2013-10-30
Title of Journal:PLoS ONE
Journal Abbrev.:PLoS One
Issue / Number:10
Start Page:1
End Page:14
Sequence Number of Article:e78384
Review Status:Peer-review
Audience:Experts Only
Intended Educational Use:No
Abstract / Description:The globular 25 kDa protein cytosine monophosphate kinase (CMPK, EC ID: from E. coli belongs to the family of nucleoside monophosphate (NMP) kinases (NMPK). Many proteins of this family share medium to high sequence and high structure similarity including the frequently found α/β topology. A unique feature of CMPK in the family of NMPKs is the positioning of a single cis−proline residue in the CORE−domain (cis−Pro124) in conjunction with a large insert in the NMP binding domain. This insert is not found in other well studied NMPKs such as AMPK or UMP/CMPK. We have analyzed the folding pathway of CMPK using time resolved tryptophan and FRET fluorescence as well as CD. Our results indicate that unfolding at high urea concentrations is governed by a single process, whereas refolding in low urea concentrations follows at least a three step process which we interpret as follows: Pro124 in the CORE−domain is in cis in the native state (N(c)) and equilibrates with its trans−isomer in the unfolded state (U(c) − U(t)). Under refolding conditions, at least the U(t) species and possibly also the U(c) species undergo a fast initial collapse to form intermediates with significant amount of secondary structure, from which the trans−Pro124 fraction folds to the native state with a 100−fold lower rate constant than the cis−Pro124 species. CMPK thus differs from homologous NMP kinases like UMP/CMP kinase or AMP kinase, where folding intermediates show much lower content of secondary structure. Importantly also unfolding is up to 100−fold faster compared to CMPK. We therefore propose that the stabilizing effect of the long NMP−domain insert in conjunction with a subtle twist in the positioning of a single cis−Pro residue allows for substantial stabilization compared to other NMP kinases with α/β topology
External Publication Status:published
Document Type:Article
Version Comment:Automatic journal name synchronization
Communicated by:wkaiser
Affiliations:MPI für medizinische Forschung/Abteilung Biomolekulare Mechanismen
MPI für medizinische Forschung/Abteilung Biomolekulare Mechanismen/Molecular chaperones
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