Thermodynamic Instability of Human 6 Light Chains: Correlation with Fibrillogenicity
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- 作者：Jonathan Wall ; Maria Schell ; Charles Murphy ; Rudi Hrncic ; Fred J. Stevens ; and Alan Solomon
- 刊名：Biochemistry
- 出版年：1999
- 出版时间：October 19, 1999
- 年：1999
- 卷：38
- 期：42
- 页码：14101 - 14108
- 全文大小：261K
- 年卷期：v.38,no.42(October 19, 1999)
- ISSN：1520-4995
文摘
Certain types of human light chains have the propensity to deposit pathologically as amyloidfibrils as evidenced by the preferential association of monoclonal 
6 proteins with AL amyloidosis.However, the molecular features that render such proteins amyloidogenic have not been elucidated. Basedupon the demonstrated relationship between the thermodynamic stability of light chains and their propensityto aggregate in vitro, we have initiated studies where the thermodynamic properties and fibrillogenicpotential of two recombinant (r) V6 molecules were compared. The first protein was generated fromcDNA cloned from marrow-derived plasma cells from a patient (Wil) who had AL amyloidosis and renalamyloid deposits; the second was from a patient (Jto) with multiple myeloma in whom the 6 proteinwas deposited not as amyloid but in the form of renal tubular casts. The thermodynamic stabilities ofrV6Wil and -Jto were determined from chaotropic and thermal denaturation studies. Based upon the
GH2O, H, G25 
C, Tm, and Cm values, the rV6Wil was less stable than its nonamyloidogenic counterpart,rV6Jto. Measurement of fibril formation using a novel in vitro fibril forming assay demonstrated thatalthough both rV6 proteins formed fibrils in vitro, Wil had a shorter lag time and exhibited faster kineticsunder physiologic conditions. Comparative amino acid sequence analyses of these two components andother 6 amyloid-associated light chains revealed that the Jto protein had certain primary structural featuresthat we posit contributed to its increased stability and thus rendered this protein nonamyloidogenic. Ourstudies provide the first evidence that stabilizing interactions within the VL domain can influence thekinetics of light chain fibrillogenicity.
6 proteins with AL amyloidosis.However, the molecular features that render such proteins amyloidogenic have not been elucidated. Basedupon the demonstrated relationship between the thermodynamic stability of light chains and their propensityto aggregate in vitro, we have initiated studies where the thermodynamic properties and fibrillogenicpotential of two recombinant (r) V6 molecules were compared. The first protein was generated fromcDNA cloned from marrow-derived plasma cells from a patient (Wil) who had AL amyloidosis and renalamyloid deposits; the second was from a patient (Jto) with multiple myeloma in whom the 6 proteinwas deposited not as amyloid but in the form of renal tubular casts. The thermodynamic stabilities ofrV6Wil and -Jto were determined from chaotropic and thermal denaturation studies. Based upon theGH2O, H, G25 C, Tm, and Cm values, the rV6Wil was less stable than its nonamyloidogenic counterpart,rV6Jto. Measurement of fibril formation using a novel in vitro fibril forming assay demonstrated thatalthough both rV6 proteins formed fibrils in vitro, Wil had a shorter lag time and exhibited faster kineticsunder physiologic conditions. Comparative amino acid sequence analyses of these two components andother 6 amyloid-associated light chains revealed that the Jto protein had certain primary structural featuresthat we posit contributed to its increased stability and thus rendered this protein nonamyloidogenic. Ourstudies provide the first evidence that stabilizing interactions within the VL domain can influence thekinetics of light chain fibrillogenicity.