Three States of the pFh-Fragment (Hinge Region) from Human Myeloma IgG3 Kuc with Native-Like Secondary Structure

V. M. Tischenko^1,2

¹Institute of Biological Instrumentation, Russian Academy of Sciences, Pushchino, Moscow Region, 142292 Russia

²Institute of Immunological Engineering, State Concern Biopreparat, Lyubuchany, Moscow Region, 142380 Russia; fax: (095) 924-0493; E-mail: tischen@vega.protres.ru

Received November 18, 1999; Revision received May 3, 2000

---

The structure of the pFh-fragment (hinge region) from human myeloma IgG3 Kuc (the third subclass immunoglobulin) was studied by hydrodynamic methods in the pH range from 3.0 to 8.0. The pFh-fragment was found to occur in three states, each with a high content of the secondary structure: a rod-like state at pH <= 4.0, a “molten globule” state at pH 4.2-5.5, and the native state at pH 7.5-8.0.

---

KEY WORDS: hinge region, pFh-fragment, viscosity, compact structure, cooperative transition, “molten globule”

---