title: Ferrous iron chelating property of low-molecular weight succinoglycans isolated from Sinorhizobium meliloti.
abstract: Iron is an essential nutrient for nitrogen-fixing legume root nodules, and the chelation of ferrous iron plays an important role in the mobility and availability of iron to the legume. In the present study, we investigated the iron-binding properties of low-molecular weight succinoglycans isolated from the nitrogen-fixing bacterium, Sinorhizobium meliloti. The low-molecular weight succinoglycans comprising three monomers (M1-M3), four dimers (D1-D4), and six trimers (T1-T6) of the succinoglycan repeating unit were purified by various chromatographic techniques. Interestingly, the colorimetric ferrozine method showed that the succinoglycans T6, M3, and D3 demonstrated a ferrous iron chelating ability of 83, 63, and 38 % per mg, respectively. The individual binding constants were determined as 43703, 2313, and 760 M(-1) for succinoglycans T6, M3, and D3 using ultraviolet-visible spectroscopy. The complexation of succinoglycan and ferrous iron can cause structural changes, which were analyzed by circular dichroism spectroscopy. Furthermore, the complex could provide antioxidant activity through an anti-Fenton reaction. These results demonstrate that the low-molecular weight succinoglycans can effectively modulate iron biochemistry as a novel ferrous iron-acquisition system of S. meliloti.
authors: Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center & Center for Biotechnology Research in UBITA, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul, 143-701, South Korea.
authors: Eunae
authors: E
authors: Cho
authors: Jae Min
authors: JM
authors: Choi
authors: Hwanhee
authors: H
authors: Kim
authors: Muhammad Nazir
authors: MN
authors: Tahir
authors: Youngjin
authors: Y
authors: Choi
authors: Seunho
authors: S
authors: Jung
mesh_terms: D000975:Antioxidants; D007501:Iron / Q000737:chemistry / Q000378:metabolism*; D007502:Iron Chelating Agents / Q000737:chemistry*; D000455:Medicago sativa / Q000382:microbiology; D018517:Plant Roots / Q000378:metabolism / Q000382:microbiology; D011135:Polysaccharides, Bacterial / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D016962:Sinorhizobium meliloti / Q000737:chemistry / Q000378:metabolism
chemical_list: D000975:Antioxidants; D007502:Iron Chelating Agents; D011135:Polysaccharides, Bacterial; C056779:succinoglycan; D007501:Iron