Merck
  • 主页
  • 查找结果
  • The extracellular heme-binding protein HbpS from the soil bacterium Streptomyces reticuli is an aquo-cobalamin binder.

The extracellular heme-binding protein HbpS from the soil bacterium Streptomyces reticuli is an aquo-cobalamin binder.

The Journal of biological chemistry (2014-10-25)
Darío Ortiz de Orué Lucana, Sergey N Fedosov, Ina Wedderhoff, Edith N Che, Andrew E Torda
摘要

The extracellular protein HbpS from Streptomyces reticuli interacts with iron ions and heme. It also acts in concert with the two-component sensing system SenS-SenR in response to oxidative stress. Sequence comparisons suggested that the protein may bind a cobalamin. UV-visible spectroscopy confirmed binding (Kd = 34 μm) to aquo-cobalamin (H2OCbl(+)) but not to other cobalamins. Competition experiments with the H2OCbl(+)-coordinating ligand CN(-) and comparison of mutants identified a histidine residue (His-156) that coordinates the cobalt ion of H2OCbl(+) and substitutes for water. HbpS·Cobalamin lacks the Asp-X-His-X-X-Gly motif seen in some cobalamin binding enzymes. Preliminary tests showed that a related HbpS protein from a different species also binds H2OCbl(+). Furthermore, analyses of HbpS-heme binding kinetics are consistent with the role of HbpS as a heme-sensor and suggested a role in heme transport. Given the high occurrence of HbpS-like sequences among Gram-positive and Gram-negative bacteria, our findings suggest a great functional versatility among these proteins.

材料
货号
品牌
产品描述

Sigma-Aldrich
L-组氨酸, ReagentPlus®, ≥99% (TLC)
Sigma-Aldrich
维生素 B 12, ≥98%
Sigma-Aldrich
L-组氨酸, suitable for cell culture, meets EP, USP testing specifications, from non-animal source
Supelco
维生素B12, pharmaceutical secondary standard, certified reference material
Sigma-Aldrich
维生素 B 12, BioReagent, suitable for cell culture, suitable for insect cell culture, suitable for plant cell culture, ≥98%
SAFC
L-组氨酸
Supelco
腈钴胺(维生素 B12), analytical standard
Sigma-Aldrich
L-组氨酸, BioUltra, ≥99.5% (NT)
Supelco
维生素B12标准液 CRM 溶液, 1.0 mg/mL in methanol, ampule of 1 mL, certified reference material, Cerilliant®
Sigma-Aldrich
氰钴胺, meets USP testing specifications
氰钴胺, European Pharmacopoeia (EP) Reference Standard
组氨酸, European Pharmacopoeia (EP) Reference Standard
Supelco
L-组氨酸, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
氰钴胺, tested according to Ph. Eur.
Supelco
L-组氨酸, certified reference material, TraceCERT®