Structural and Thermodynamic Characteristics of Amyloidogenic Intermediates of β-2-Microglobulin.
β-2-microglobulin (β2m) self-aggregates to form amyloid fibril in renal patients taking long-term dialysis treatment. Despite the extensive structural and mutation studies carried out so far, the molecular details on the factors that dictate amyloidogenic potential of β2m remain elusive. Here we report molecular dynamics simulations followed by the solvation thermodynamic analyses on the wild-type β2m and D76N, D59P, and W60C mutants at the native (N) and so-called aggregation-prone intermediate (IT) states, which are distinguished by the native cis- and non-native trans-Pro32 backbone conformations. Three major structural and thermodynamic characteristics of the IT-state relative to the N-state in β2m protein are detected that contribute to the increased amyloidogenic potential: (i) the disruption of the edge D-strand, (ii) the increased solvent-exposed hydrophobic interface, and (iii) the increased solvation free energy (less affinity toward solvent water). Mutation effects on these three factors are shown to exhibit a good correlation with the experimentally observed distinct amyloidogenic propensity of the D76N (+), D59P (+), and W60C (-) mutants (+/- for enhanced/decreased). Our analyses thus identify the structural and thermodynamic characteristics of the amyloidogenic intermediates, which will serve to uncover molecular mechanisms and driving forces in β2m amyloid fibril formation.
Department of Chemistry, Sookmyung Women's University, Cheongpa-ro-47-gil 100, Yongsan-ku, Seoul, 140-742, Korea.
Song-Ho
SH
Chong
Department of Chemistry, Sookmyung Women's University, Cheongpa-ro-47-gil 100, Yongsan-ku, Seoul, 140-742, Korea.
Jooyeon
J
Hong
Department of Chemistry, Sookmyung Women's University, Cheongpa-ro-47-gil 100, Yongsan-ku, Seoul, 140-742, Korea.
Sulgi
S
Lim
Department of Chemistry, Sookmyung Women's University, Cheongpa-ro-47-gil 100, Yongsan-ku, Seoul, 140-742, Korea.
Sunhee
S
Cho
Department of Chemistry, Sookmyung Women's University, Cheongpa-ro-47-gil 100, Yongsan-ku, Seoul, 140-742, Korea.
Jinkeong
J
Lee
Department of Chemistry, Sookmyung Women's University, Cheongpa-ro-47-gil 100, Yongsan-ku, Seoul, 140-742, Korea.
Sihyun
S
Ham
D058227:Amyloidogenic Proteins / Q000737:chemistry*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D056004:Molecular Dynamics Simulation; D009154:Mutation; D011487:Protein Conformation; D055550:Protein Stability; D012997:Solvents; D013816:Thermodynamics; D001613:beta 2-Microglobulin / Q000737:chemistry* / Q000235:genetics
D058227:Amyloidogenic Proteins; D012997:Solvents; D001613:beta 2-Microglobulin