The coordination geometries around the copper ion of plastocyanin (a blue-copper protein) in oxidized and reduced form, respectively, are
To understand the coordination geometries around the copper ion of plastocyanin in oxidized and reduced forms, we need to delve into the structural characteristics of this blue-copper protein.
Plastocyanin is a type of protein that contains a single copper ion. It plays a crucial role in electron transfer during photosynthesis. The geometry around the copper center in plastocyanin is typically categorized under the class of ‘blue-copper’ proteins, known for their peculiar electronic and geometric properties.
In both oxidized and reduced forms, plastocyanin has a distorted tetrahedral geometry around the copper ion. Here's why:
- Copper Coordination in Plastocyanin: The copper in plastocyanin is coordinated by two nitrogen atoms from histidine ligands, one sulfur atom from cysteine, and one sulfur atom from methionine. This arrangement forms a distorted tetrahedral geometry.
- Oxidation States and Geometry: The copper can exist in the +1 or +2 oxidation state. However, the distortion in tetrahedral geometry remains consistent across these states. The geometry is termed 'distorted' due to slight deviations caused by the protein's 3D structure and the varying ligand field.
Given this understanding, the appropriate choice is:
Distorted tetrahedral for both oxidized and reduced forms.
Other options such as "tetrahedral and square-planar," "square-planar and tetrahedral," and "ideal tetrahedral for both" do not correctly describe the consistent geometrical distortion experienced by the copper center in plastocyanin.
Thus, the correct answer is indeed distorted tetrahedral for both.
Important Questions from Bioinorganic Chemistry
Consider the following transformation reactions in the context of co - enzyme B12
A. 1, 2 - Carbon shift
B. Hydration of CO2
C. Benzene to phenol
D. Dimethyl sulfide to dimethyl sulfoxide
The correct statement(s) for co - enzyme B12 is / are
During the binding of O2 to myoglobin (consider 'heme' in xy-plane), the molecular orbital of O2 and atomic orbital of Fe involved in the formation of the σ-bond is
In the catalytic cycle of Cytochrome P450, the generation of [(porphyrin)+•FeIV(O)] from [(porphyrin)FeIII(OOH)] involves
Match List I with List II
List I
List II
Metalloprotein
Metal
A.
carboxypeptidase A
I.
Mn
B.
oxygen-evolving complex
II.
Fe
C.
hemerythrin
III.
Ni
D.
coenzyme F-430
IV.
Zn
Choose the correct answer from the options given below:
In solution, Vaska's complex is known to bind O2 reversibly. In the product, oxidation state of the metal ion center coordination geometry and mode of binding of O2, respectively are
