Structure and dynamics of coxsackievirus B4 2A proteinase, an enyzme involved in the etiology of heart disease.
The 2A proteinases (2A(pro)) from the picornavirus family are multifunctional cysteine proteinases that perform essential roles during viral replication, involving viral polyprotein self-processing and shutting down host cell protein synthesis through cleavage of the eukaryotic initiation factor 4G (eIF4G) proteins. Coxsackievirus B4 (CVB4) 2A(pro) also cleaves heart muscle dystrophin, leading to cytoskeletal dysfunction and the symptoms of human acquired dilated cardiomyopathy. We have determined the solution structure of CVB4 2A(pro) (extending in an N-terminal direction to include the C-terminal eight residues of CVB4 VP1, which completes the VP1-2A(pro) substrate region). In terms of overall fold, it is similar to the crystal structure of the mature human rhinovirus serotype 2 (HRV2) 2A(pro), but the relatively low level (40%) of sequence identity leads to a substantially different surface. We show that differences in the cI-to-eI2 loop between HRV2 and CVB4 2A(pro) translate to differences in the mechanism of eIF4GI recognition. Additionally, the nuclear magnetic resonance relaxation properties of CVB4 2A(pro), particularly of residues G1 to S7, F64 to S67, and P107 to G111, reveal that the substrate region is exchanging in and out of a conformation in which it occupies the active site with association and dissociation rates in the range of 100 to 1,000 s(-1). This exchange influences the conformation of the active site and points to a mechanism for how self-processing can occur efficiently while product inhibition is avoided.
Baxter
Nicola J
NJ
Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, United Kingdom.
Roetzer
Andreas
A
Liebig
Hans-Dieter
HD
Sedelnikova
Svetlana E
SE
Hounslow
Andrea M
AM
Skern
Tim
T
Waltho
Jonathan P
JP
D000595:Amino Acid Sequence; D002311:Cardiomyopathy, Dilated / Q000201:enzymology / Q000209:etiology* / Q000821:virology; D020134:Catalytic Domain; D003384:Coxsackievirus Infections / Q000150:complications / Q000201:enzymology; D003546:Cysteine Endopeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D029822:Enterovirus B, Human / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D012229:Rhinovirus / Q000201:enzymology / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D055672:Static Electricity; D013816:Thermodynamics; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D014764:Viral Proteins; D003546:Cysteine Endopeptidases; C057400:picornain 2A, Picornavirus