Structural And Dynamic Effects Of Alpha-Helix Deletion In Sso7d: Implications For Protein Thermal Stability(612 views) Merlino A, Graziano G, Mazzarella L
Proteins (ISSN: 0887-3585, 1097-0134, 1097-0134electronic), 2004 Dec 1; 57(4): 692-701.
Keywords: Essential Dynamics, Hyperthermophilic Protein, Molecular Dynamics, Sso7d, Thermal Stability, Unfolding Pathway, Bacterial Protein, Leucine, Protein Sso7d, Unclassified Drug, Alpha Helix, Amino Terminal Sequence, Article, Beta Sheet, Carboxy Terminal Sequence, Computer Model, Nonhuman, Nuclear Magnetic Resonance Spectroscopy, Priority Journal, Protein Engineering, Protein Folding, Protein Stability, Protein Structure, Site Directed Mutagenesis, Sulfolobus Solfataricus, Thermostability, X Ray Analysis, Amino Acids, Archaeal Proteins, Computer Simulation, Dna-Binding Proteins, Mutation, Secondary, Tertiary, Sequence Deletion, Thermodynamics, Time Factors, Water,
Affiliations: *** IBB - CNR ***
Dipto. di Scienze Farmaceutiche, Università di Salerno, Fisciano, Italy
Dipartimento di Chimica, Universita di Napoli Federico II, Napoli, Italy
Dipto. di Sci. Biol. ed Ambientali, Università del Sannio, Benevento, Italy
Ist. di Biostrutture e Bioimmagini, CNR, Via Mezzocannone, 6, 80134 Napoli, Italy
References: Not available.
Structural And Dynamic Effects Of Alpha-Helix Deletion In Sso7d: Implications For Protein Thermal Stability
Sso7d is a 62-residue protein from the hyperthemophilic archaeon Sulfolobus solfataricus with a denaturation temperature close to 100degreesC around neutral pH. An engineered form of Sso7d truncated at leucine 54 (L54Delta) is significantly less stable, with a denaturation temperature of 53degreesC. Molecular dynamics (MD) studies of Sso7d. and its truncated form at two different temperatures have been performed. The results of the MD simulations at 300 K indicate that: (1) the flexibility of Sso7d chain at 300 K agrees with that detected from X-ray and NMR structural studies; (2) L54Delta remains stable in the native folded conformation and possesses an overall dynamic behavior similar to that of the parent protein. MD simulations performed at 500 K, 10 ns long, indicate that, while Sso7d is in-silico resistant to high temperature, the truncated variant partially unfolds, revealing the early phases of the thermal unfolding pathway of the protein. Analysis of the trajectories of L54Delta suggests that the unzipping of the N-terminal and C-terminal beta-strands should be the first event of the unfolding pathway, and points out the regions more resistant to thermal unfolding. These findings allow one to understand the role played by specific interactions connecting the two ends of the chain for the high thermal stability of Sso7d, and support recent hypotheses on its folding mechanism emerged from site-directed mutagenesis studies. (C) 2004Wiley-Liss, Inc
Structural And Dynamic Effects Of Alpha-Helix Deletion In Sso7d: Implications For Protein Thermal Stability