26:
220:
392:
441:
514:, which can be found in oceanic environments. It was surprising to find these organisms containing the protein plastocyanin because the concentration of copper dissolved in the ocean is usually low (between 0.4 – 50 nM). However, the concentration of copper in the oceans is comparatively higher compared to the concentrations of other metals such as
428:
Cu(II) site instead of a perfectly symmetric tetrahedral geometry. A feature of the entatic state is a protein environment that is capable of preventing ligand dissociation even at a high enough temperature to break the metal-ligand bond. In the case of plastocyanin, it has been experimentally determined through
485:
bond (2.1Å), increasing its electron donating strength. Overall, plastocyanin exhibits a lower reorganization energy due to the entatic state of the protein ligand enforcing the same distorted tetrahedral geometry in both the Cu(II) and Cu(I) oxidation states, enabling it to perform electron transfer
427:
between Cu(I) and Cu(II), and it was first theorized that its entatic state was a result of the protein imposing an undistorted tetrahedral geometry preferred by ordinary Cu(I) complexes onto the oxidized Cu(II) site. However, a highly distorted tetrahedral geometry is induced upon the oxidized
295:
While the molecular surface of the protein near the copper binding site varies slightly, all plastocyanins have a hydrophobic surface surrounding the exposed histidine of the copper binding site. In plant plastocyanins, acidic residues are located on either side of the highly conserved
419:. This distorted geometry is less stable than ideal tetrahedral geometry due to its lower ligand field stabilization as a result of the trigonal distortion. This unusual geometry is induced by the rigid “pre-organized” conformation of the ligand donors by the protein, which is an
364:
where it increases the energy of the reactants, decreasing the amount of energy needed for the redox reaction to occur. Another way to rephrase the function of plastocyanin is that it can facilitate the electron transfer reaction by providing a small
522:. Other organisms that live in the ocean, such as other phytoplankton species, have adapted to where they do not need as high of concentrations of these low concentration metals (Fe and Zn) to facilitate photosynthesis and grow.
744:
Anderson GP, Sanderson DG, Lee CH, Durell S, Anderson LB, Gross EL (December 1987). "The effect of ethylenediamine chemical modification of plastocyanin on the rate of cytochrome f oxidation and P-700+ reduction".
436:
bond that should dissociate at physiological temperature due to increased entropy. However, this bond does not dissociate due to the constraints of the protein environment dominating over the entropic forces.
460:
In ordinary copper complexes involved in Cu(I)/Cu(II) redox coupling without a constraining protein environment, their ligand geometry changes significantly, and typically corresponds to the presence of a
486:
at a faster rate. The reorganization energy of blue copper proteins such as plastocyanin from 0.7 to 1.2 eV (68-116 kJ/mol) compared to 2.4 eV (232 kJ/mol) in an ordinary copper complex such as .
360:) reaction. Plastocyanin is believed to work less like an enzyme where enzymes decrease the transition energy needed to transfer the electron. Plastocyanin works more on the principles of
911:
Solomon EI, Szilagyi RK, DeBeer George S, Basumallick L (February 2004). "Electronic structures of metal sites in proteins and models: contributions to function in blue copper proteins".
340:
After dissociation, CuPc diffuses through the lumen space until recognition/binding occurs with P700, at which point P700 oxidizes CuPc according to the following reaction:
253:, spinach, and French bean plants have been characterized crystallographically. In all cases the binding site is generally conserved. Bound to the copper center are four
324:
patch is always present. These hydrophobic and acidic patches are believed to be the recognition/binding sites for the other proteins involved in electron transfer.
277:) than Cu-S (Met) (282 pm) bond. The elongated Cu-thioether bond appears to destabilise the Cu state thereby enhancing its oxidizing power. The blue colour (597
1006:
Randall DW, Gamelin DR, LaCroix LB, Solomon EI (February 2000). "Electronic structure contributions to electron transfer in blue Cu and Cu(A)".
316:
plastocyanins and variations among different bacterial species is large. Many cyanobacterial plastocyanins have 107 amino acids. Although the
273:. The geometry of the copper binding site is described as a ‘distorted tetrahedral’. The Cu-S (Cys) contact is much shorter (207
308:, contain similar acidic residues but are shaped differently from those of plant plastocyanins—they lack residues 57 and 58. In
1114:
990:
701:
474:
89:
1124:
Sato K, Kohzuma T, Dennison C (February 2003). "Active-site structure and electron-transfer reactivity of plastocyanins".
1178:
121:
412:
1168:
1049:
Peers G, Price NM (May 2006). "Copper-containing plastocyanin used for electron transport by an oceanic diatom".
416:
717:
Gewirth AA, Solomon EI (June 1988). "Electronic structure of plastocyanin: excited state spectral features".
465:. However, the Jahn-Teller distorting force is not present in plastocyanin due to a large splitting of the d
332:
Plastocyanin (CuPc) is reduced (an electron is added) by cytochrome f according to the following reaction:
232:
592:
Redinbo MR, Yeates TO, Merchant S (February 1994). "Plastocyanin: structural and functional analysis".
109:
102:
114:
1173:
211:. Cytochrome f acts as an electron donor while P700+ accepts electrons from reduced plastocyanin.
151:. Specifically, it falls into the group of small type I blue copper proteins called "cupredoxins".
1163:
429:
780:
Ratajczak R, Mitchell R, Haehnel W (1988). "Properties of the oxidizing site of
Photosystem I".
462:
190:
168:
366:
228:
1058:
541:"Cupredoxins--a study of how proteins may evolve to use metals for bioenergetic processes"
481:
bond (2.9Å) with decreased electron donation strength. This bond also shortens the Cu(I)-S
25:
8:
377:
203:
and P700 are both membrane-bound proteins with exposed residues on the lumen-side of the
1062:
223:
The copper site in plastocyanin, with the four amino acids that bind the metal labelled.
1082:
1031:
885:
860:
836:
811:
666:
641:
617:
565:
540:
381:
1141:
1110:
1074:
1023:
986:
963:
946:
Solomon EI, Hadt RG (2011). "Recent advances in understanding blue copper proteins".
928:
890:
841:
793:
762:
758:
697:
671:
609:
570:
373:
136:
94:
38:
1035:
1133:
1086:
1066:
1015:
955:
920:
880:
872:
831:
823:
789:
754:
726:
661:
653:
621:
601:
560:
552:
70:
384:
simulations. This method was used to determine that plastocyanin has an entatic
692:, Guss JM (2001). "Plastocyanin". In Bode W, Messerschmidt A, Cygler M (eds.).
372:
To study the properties of the redox reaction of plastocyanin, methods such as
182:
160:
148:
144:
140:
959:
227:
Plastocyanin was the first of the blue copper proteins to be characterised by
219:
1157:
967:
503:
499:
495:
420:
385:
369:, which has been measured to about 16–28 kcal/mol (67–117 kJ/mol).
361:
309:
186:
77:
1145:
1078:
1027:
932:
924:
876:
845:
689:
657:
574:
391:
208:
164:
1019:
894:
766:
675:
613:
98:
356:
A catalyst's function is to increase the speed of the electron transfer (
321:
235:
1070:
730:
440:
312:, the distribution of charged residues on the surface is different from
910:
605:
556:
348:
The redox potential is about 370 mV and the isoelectric pH is about 4.
313:
270:
31:
1137:
827:
477:). Additionally, the structure of plastocyanin exhibits a long Cu(I)-S
396:
42:
399:
showing the distorted tetrahedral geometry with the elongated Cu(I)-S
278:
274:
262:
258:
204:
696:. Vol. 2. Chichester: John Wiley & Sons. pp. 1153–69.
444:
Copper site of
Plastocyanin showing the large splitting of the Cu d
305:
297:
281:
peak absorption) is assigned to a charge transfer transition from S
266:
65:
812:"A QM/MM study of the nature of the entatic state in plastocyanin"
82:
254:
250:
1109:. Sausalito, Calif: University Science Books. pp. 237–242.
292:
In the reduced form of plastocyanin, His-87 becomes protonated.
861:"Crystal structure of spinach plastocyanin at 1.7 A resolution"
642:"Crystal structure of spinach plastocyanin at 1.7 A resolution"
507:
317:
239:
163:, plastocyanin functions as an electron transfer agent between
139:. It is found in a variety of plants, where it participates in
579:(for an overview of the various types of blue copper proteins)
494:
Usually, plastocyanin can be found in organisms that contain
424:
357:
301:
246:
1005:
304:
plastocyanins, and those from vascular plants in the family
519:
515:
743:
983:
Biological
Inorganic Chemistry: Structure and reactivity
779:
858:
639:
591:
1105:
Berg JM, Lippard SJ (1994). "Blue Copper
Proteins".
859:
Xue Y, Okvist M, Hansson O, Young S (October 1998).
640:
Xue Y, Okvist M, Hansson O, Young S (October 1998).
1123:
747:
Biochimica et
Biophysica Acta (BBA) - Bioenergetics
423:. Plastocyanin performs electron transfer with the
809:
415:, however plastocyanin has a trigonally distorted
1155:
411:Four-coordinate copper complexes often exhibit
716:
135:is a copper-containing protein that mediates
810:Hurd CA, Besley NA, Robinson D (June 2017).
538:
388:of about 10 kcal/mol (42 kJ/mol).
265:residues (His37 and His87), the thiolate of
1104:
945:
688:
320:patches are not conserved in bacteria, the
1048:
852:
506:. Plastocyanin has also been found in the
24:
1008:Journal of Biological Inorganic Chemistry
985:. University Science Books. p. 253.
884:
835:
665:
594:Journal of Bioenergetics and Biomembranes
564:
1126:Journal of the American Chemical Society
439:
390:
218:
980:
245:Structures of the protein from poplar,
1156:
906:
904:
805:
803:
539:Choi M, Davidson VL (February 2011).
432:that there is a long and weak Cu(I)-S
147:, a family of intensely blue-colored
143:. The protein is a prototype of the
1107:Principles of bioinorganic chemistry
635:
633:
631:
587:
585:
901:
13:
1097:
816:Journal of Computational Chemistry
800:
14:
1190:
628:
582:
475:Blue Copper Protein Entatic State
395:Copper site of Plastocyanin from
502:, as well as algae that contain
351:
231:. It features an eight-stranded
1042:
999:
974:
939:
489:
948:Coordination Chemistry Reviews
773:
737:
710:
682:
532:
1:
525:
794:10.1016/0005-2728(88)90038-2
759:10.1016/0005-2728(87)90117-4
463:Jahn-Teller distorting force
327:
214:
7:
694:Handbook of metalloproteins
154:
10:
1195:
1179:Electron-transfer proteins
960:10.1016/j.ccr.2010.12.008
129:Electron transfer protein
120:
108:
88:
76:
64:
56:
51:
23:
18:
430:absorption spectroscopy
1169:Coordination complexes
925:10.1002/chin.200420281
877:10.1002/pro.5560071006
782:Biochim. Biophys. Acta
658:10.1002/pro.5560071006
512:Thalassiosira oceanica
457:
413:square planar geometry
408:
224:
1020:10.1007/s007750050003
443:
403:and shortened Cu(I)-S
394:
367:reorganization energy
269:and the thioether of
229:X-ray crystallography
222:
417:tetrahedral geometry
145:blue copper proteins
1071:10.1038/nature04630
1063:2006Natur.441..341P
731:10.1021/ja00220a015
378:molecular mechanics
981:Bertini G (2007).
606:10.1007/BF00763219
557:10.1039/c0mt00061b
458:
409:
382:molecular dynamics
225:
1138:10.1021/ja021005u
1116:978-0-935702-72-9
1057:(7091): 341–344.
992:978-1-891389-43-6
828:10.1002/jcc.24666
822:(16): 1431–1437.
703:978-0-471-62743-2
652:(10): 2099–2105.
374:quantum mechanics
137:electron-transfer
127:
126:
1186:
1149:
1132:(8): 2101–2112.
1120:
1091:
1090:
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1040:
1039:
1003:
997:
996:
978:
972:
971:
954:(7–8): 774–789.
943:
937:
936:
913:Chemical Reviews
908:
899:
898:
888:
871:(10): 2099–105.
856:
850:
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839:
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771:
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536:
45:
28:
16:
15:
1194:
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1183:
1174:Copper proteins
1154:
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1117:
1100:
1098:Further reading
1095:
1094:
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1043:
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993:
979:
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865:Protein Science
857:
853:
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742:
738:
715:
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704:
687:
683:
646:Protein Science
638:
629:
590:
583:
537:
533:
528:
492:
484:
480:
472:
468:
455:
451:
447:
435:
406:
402:
354:
344:CuPc → CuPc + e
336:CuPc + e → CuPc
330:
288:
284:
238:containing one
217:
197:
185:and P700+ from
175:
157:
149:metalloproteins
130:
47:
37:
12:
11:
5:
1192:
1182:
1181:
1176:
1171:
1166:
1164:Photosynthesis
1151:
1150:
1121:
1115:
1101:
1099:
1096:
1093:
1092:
1041:
998:
991:
973:
938:
919:(2): 419–458.
900:
851:
799:
788:(2): 306–318.
772:
753:(3): 386–398.
736:
725:(12): 3811–9.
709:
702:
681:
627:
581:
551:(2): 140–151.
530:
529:
527:
524:
491:
488:
482:
478:
473:orbitals (See
470:
466:
453:
449:
445:
433:
404:
400:
362:entatic states
353:
350:
346:
345:
338:
337:
329:
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286:
282:
261:groups of two
216:
213:
195:
183:photosystem II
173:
161:photosynthesis
156:
153:
141:photosynthesis
128:
125:
124:
122:UniProt Family
118:
117:
112:
106:
105:
92:
86:
85:
80:
74:
73:
68:
62:
61:
58:
54:
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36:plastocyanin,
29:
21:
20:
9:
6:
4:
3:
2:
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719:J Am Chem Soc
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558:
554:
550:
546:
542:
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531:
523:
521:
517:
513:
509:
505:
504:chlorophyll c
501:
500:cyanobacteria
497:
496:chlorophyll b
487:
476:
464:
442:
438:
431:
426:
422:
421:entatic state
418:
414:
398:
393:
389:
387:
386:strain energy
383:
379:
375:
370:
368:
363:
359:
352:Entatic state
349:
343:
342:
341:
335:
334:
333:
325:
323:
319:
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311:
310:cyanobacteria
307:
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188:
187:photosystem I
184:
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55:
50:
44:
40:
35:
33:
27:
22:
17:
1129:
1125:
1106:
1054:
1050:
1044:
1014:(1): 16–29.
1011:
1007:
1001:
982:
976:
951:
947:
941:
916:
912:
868:
864:
854:
819:
815:
785:
781:
775:
750:
746:
739:
722:
718:
712:
693:
684:
649:
645:
600:(1): 49–66.
597:
593:
548:
544:
534:
511:
493:
490:In the ocean
459:
410:
371:
355:
347:
339:
331:
294:
291:
244:
233:antiparallel
226:
209:chloroplasts
207:membrane of
198:
192:
176:
170:
165:cytochrome f
158:
133:Plastocyanin
132:
131:
60:Plastocyanin
30:
19:Plastocyanin
545:Metallomics
322:hydrophobic
191:Cytochrome
169:cytochrome
52:Identifiers
1158:Categories
690:Freeman HC
526:References
314:eukaryotic
275:picometers
32:Phormidium
968:0010-8545
456:orbitals.
328:Reactions
263:histidine
259:imidazole
215:Structure
205:thylakoid
71:IPR002387
34:laminosum
1146:12590538
1079:16572122
1036:20628012
1028:10766432
933:14871131
846:27859435
575:21258692
397:PDB 1AG6
380:(QM/MM)
306:Apiaceae
298:tyrosine
242:center.
236:β-barrel
155:Function
66:InterPro
46:.
1087:4379844
1059:Bibcode
895:9792096
886:2143848
837:5434870
767:3689779
676:9792096
667:2143848
622:2662584
614:8027022
566:6916721
255:ligands
251:parsley
201:complex
179:complex
167:of the
115:cd04219
1144:
1113:
1085:
1077:
1051:Nature
1034:
1026:
989:
966:
931:
893:
883:
844:
834:
765:
700:
674:
664:
620:
612:
573:
563:
508:diatom
407:bonds.
318:acidic
300:-83.
257:: the
240:copper
103:SUPFAM
57:Symbol
1083:S2CID
1032:S2CID
618:S2CID
469:and d
467:x2-y2
448:and S
446:x2-y2
425:redox
358:redox
302:Algal
285:to Cu
271:Met92
267:Cys84
247:algae
181:from
99:SCOPe
90:SCOP2
1142:PMID
1111:ISBN
1075:PMID
1024:PMID
987:ISBN
964:ISSN
929:PMID
891:PMID
842:PMID
763:PMID
698:ISBN
672:PMID
610:PMID
571:PMID
520:iron
518:and
516:zinc
498:and
287:dx-y
95:3BQV
83:3BQV
78:CATH
43:3BQV
1134:doi
1130:125
1067:doi
1055:441
1016:doi
956:doi
952:255
921:doi
917:104
881:PMC
873:doi
832:PMC
824:doi
790:doi
786:933
755:doi
751:894
727:doi
723:110
662:PMC
654:doi
602:doi
561:PMC
553:doi
483:Cys
479:Met
450:Cys
434:Met
405:Cys
401:Met
189:.
159:In
110:CDD
39:PDB
1160::
1140:.
1128:.
1081:.
1073:.
1065:.
1053:.
1030:.
1022:.
1010:.
962:.
950:.
927:.
915:.
903:^
889:.
879:.
867:.
863:.
840:.
830:.
820:38
818:.
814:.
802:^
784:.
761:.
749:.
721:.
670:.
660:.
648:.
644:.
630:^
616:.
608:.
598:26
596:.
584:^
569:.
559:.
547:.
543:.
510:,
471:xy
454:xy
376:/
289:.
283:pπ
279:nm
249:,
101:/
97:/
41::
1148:.
1136::
1119:.
1089:.
1069::
1061::
1038:.
1018::
1012:5
995:.
970:.
958::
935:.
923::
897:.
875::
869:7
848:.
826::
796:.
792::
769:.
757::
733:.
729::
706:.
678:.
656::
650:7
624:.
604::
577:.
555::
549:3
452:d
199:f
196:6
193:b
177:f
174:6
171:b
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
