6rpv
Extremely stable monomeric variant of human cystatin C with single amino acid substitution
Structural highlights
DiseaseCYTC_HUMAN Defects in CST3 are the cause of amyloidosis type 6 (AMYL6) [MIM:105150; also known as hereditary cerebral hemorrhage with amyloidosis (HCHWA), cerebral amyloid angiopathy (CAA) or cerebroarterial amyloidosis Icelandic type. AMYL6 is a hereditary generalized amyloidosis due to cystatin C amyloid deposition. Cystatin C amyloid accumulates in the walls of arteries, arterioles, and sometimes capillaries and veins of the brain, and in various organs including lymphoid tissue, spleen, salivary glands, and seminal vesicles. Amyloid deposition in the cerebral vessels results in cerebral amyloid angiopathy, cerebral hemorrhage and premature stroke. Cystatin C levels in the cerebrospinal fluid are abnormally low.[1] [2] Genetic variations in CST3 are associated with age-related macular degeneration type 11 (ARMD11) [MIM:611953. ARMD is a multifactorial eye disease and the most common cause of irreversible vision loss in the developed world. In most patients, the disease is manifest as ophthalmoscopically visible yellowish accumulations of protein and lipid that lie beneath the retinal pigment epithelium and within an elastin-containing structure known as Bruch membrane.[3] FunctionCYTC_HUMAN As an inhibitor of cysteine proteinases, this protein is thought to serve an important physiological role as a local regulator of this enzyme activity. Publication Abstract from PubMedHuman cystatin C (hCC), a member of the superfamily of papain-like cysteine protease inhibitors, is the most widespread cystatin in human body fluids. This small protein, in addition to its physiological function, is involved in various diseases, including cerebral amyloid angiopathy, cerebral hemorrhage, stroke, and dementia. Physiologically active hCC is a monomer. However, all structural studies based on crystallization led to the dimeric structure formed as a result of a three-dimensional exchange of the protein domains (3D domain swapping). The monomeric structure was obtained only for hCC variant V57N and for the protein stabilized by an additional disulfide bridge. With this study, we extend the number of models of monomeric hCC by an additional hCC variant with a single amino acid substitution in the flexible loop L1. The V57G variant was chosen for the X-ray and NMR structural analysis due to its exceptional conformational stability in solution. In this work we show for the first time the structural and dynamics studies of human cystatin C variant in solution. We were also able to compare these data with the crystal structure of the hCC V57G and with other cystatins. The overall cystatin fold is retained in the solute form. Additionally, structural information concerning the N-terminus was obtained during our studies and presented for the first time. This article is protected by copyright. All rights reserved. NMR and crystallographic structural studies of the extremely stable monomeric variant of human cystatin C with single amino acid substitution.,Maszota-Zieleniak M, Jurczak P, Orlikowska M, Zhukov I, Borek D, Otwinowski Z, Skowron P, Pietralik Z, Kozak M, Szymanska A, Rodziewicz-Motowidlo S FEBS J. 2019 Jul 22. doi: 10.1111/febs.15010. PMID:31330077[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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