Tris-NTA

Tris-NTA is a His-tagged protein ligand that can be used to bind His-tagged proteins^[1]. Tris-NTA is a high-affinity metal chelator composed of three nitrotriacetic acid (NTA) groups connected by a tris(hydroxymethyl)aminomethane (Tris) backbone. Tris-NTA can specifically bind to hexahistidine-tagged (His-tag) proteins and stably chelate divalent metal ions (such as Ni²⁺, Co²⁺)^{[2, 3]}. Tris-NTA has higher binding stability than single NTA ligands^[4]. Tris-NTA can be chemically modified in a variety of ways (such as coupling fluorescent groups, biotin or nanocarriers), making it suitable for applications in targeted drug delivery and molecular diagnostics^{[5, 6]}.

References:
[1] Zhu L, Chang Y, Li Y, et al. Biosensors based on the binding events of nitrilotriacetic acid–metal complexes[J]. Biosensors, 2023, 13(5): 507.
[2] Auer S, Azizi L, Faschinger F, et al. Stable immobilisation of His-tagged proteins on BLI biosensor surface using cobalt[J]. Sensors and Actuators B: Chemical, 2017, 243: 104-113.
[3] Brellier M, Barlaam B, Mioskowski C, et al. Insight into the Complexation Mode of Bis (nitrilotriacetic acid)(NTA) Ligands with Ni2+ Involved in the Labeling of Histidine‐Tagged Proteins[J]. Chemistry–A European Journal, 2009, 15(46): 12689-12701.
[4] Lata S, Reichel A, Brock R, et al. High-affinity adaptors for switchable recognition of histidine-tagged proteins[J]. Journal of the American Chemical Society, 2005, 127(29): 10205-10215.
[5] Bartoschik T, Galinec S, Kleusch C, et al. Near-native, site-specific and purification-free protein labeling for quantitative protein interaction analysis by MicroScale Thermophoresis[J]. Scientific reports, 2018, 8(1): 4977.
[6] You C, Piehler J. Multivalent chelators for spatially and temporally controlled protein functionalization[J]. Analytical and bioanalytical chemistry, 2014, 406: 3345-3357.

Tris-NTA是一种带有His标签的蛋白质配体，可用于结合带有His标签的蛋白质^[1]。Tris-NTA是一种高亲和力的金属螯合剂，由三个硝基三乙酸（NTA）基团通过三羟甲基氨基甲烷（Tris）骨架连接而成，能够特异性结合六组氨酸标签（His-tag）蛋白，并稳定螯合二价金属离子（如Ni²⁺、Co²⁺）^{[2, 3]}。Tris-NTA相较于单NTA配体具有更高的结合稳定性^[4]。Tris-NTA能够进行多种化学修饰（如偶联荧光基团、生物素或纳米载体），从而应用于靶向药物递送和分子诊断等领域^{[5, 6]}。