Kolozsi András, Jancsó Attila, Nagy Nóra V, Gajda Tamás
Department of Inorganic and Analytical Chemistry, University of Szeged, Szeged, Hungary.
J Inorg Biochem. 2009 Jul;103(7):940-7. doi: 10.1016/j.jinorgbio.2009.04.006. Epub 2009 Apr 23.
A histidine-rich peptide HSHRDFQPVLHL-NH(2) (L), identical with the N-terminal fragment of the anti-angiogenic human endostatin has been synthesized. Endostatin is a recently identified broad spectrum angiogenesis inhibitor, which inhibits 65 different tumor types. The N-terminal 25-mer peptide fragment of human endostatin has the same antitumor effect as the entire protein. The zinc(II) binding is crucial for the antitumor effect in both cases. Our peptide may provide all critical interactions for zinc(II) binding present in the N-terminal 25-mer peptide fragment. In addition, the N-terminus of human endostatin has a supposedly high affinity binding site for copper(II), similar to human serum albumin. Since copper(II) is intimately involved in angiogenesis, this may have biological relevance. In order to determine the metal binding properties of the N-terminal fragment of endostatin, we performed equilibrium, UV-visible (UV-vis), CD, EPR and NMR studies on the zinc(II) and copper(II) complexes of L. In the presence of zinc(II) the formation of a stable [NH(2),3N(im),COO(-)] coordinated complex was detected in the neutral pH-range. This coordination mode is probably identical to that present in the zinc(II) complex of the above mentioned N-terminal 25-mer peptide fragment of human endostatin. Moreover, L has extremely high copper(II) binding affinity, close to those of copper-containing metalloenzymes, and forms albumin-like [NH(2),N(-),N(-),N(im)] coordinated copper(II) complex in the neutral pH-range, which may suggest that copper(II) binding is involved in the biological activity of endostatin.
已合成了一种富含组氨酸的肽HSHRDFQPVLHL-NH₂（L），它与抗血管生成的人内皮抑素的N端片段相同。内皮抑素是最近发现的一种广谱血管生成抑制剂，可抑制65种不同的肿瘤类型。人内皮抑素的N端25肽片段与整个蛋白质具有相同的抗肿瘤作用。在这两种情况下，锌（II）结合对于抗肿瘤作用至关重要。我们的肽可能提供了存在于N端25肽片段中锌（II）结合的所有关键相互作用。此外，人内皮抑素的N端具有一个据推测对铜（II）具有高亲和力的结合位点，类似于人血清白蛋白。由于铜（II）密切参与血管生成，这可能具有生物学相关性。为了确定内皮抑素N端片段的金属结合特性，我们对L的锌（II）和铜（II）配合物进行了平衡、紫外可见（UV-vis）、圆二色（CD）、电子顺磁共振（EPR）和核磁共振（NMR）研究。在锌（II）存在下，在中性pH范围内检测到形成了稳定的[NH₂,3N(im),COO⁻]配位配合物。这种配位模式可能与上述人内皮抑素N端25肽片段的锌（II）配合物中的配位模式相同。此外，L具有极高的铜（II）结合亲和力，接近含铜金属酶的亲和力，并在中性pH范围内形成白蛋白样的[NH₂,N⁻,N⁻,N(im)]配位铜（II）配合物，这可能表明铜（II）结合参与了内皮抑素的生物活性。
