IVF0023165 (gene) Melon (IVF77) v1

Overview


Name	IVF0023165
Type	gene
Organism	Cucumis melo L. ssp. agrestis cv. IVF77 (Melon (IVF77) v1)
Description	cytochrome c oxidase assembly factor 6
Location	chr02: 12218271 .. 12222625 (+)
RNA-Seq Expression	IVF0023165
Synteny	IVF0023165

Sequences

The following sequences are available for this feature:

Gene sequence (with intron)

Legend: five_prime_UTRexonCDSpolypeptidethree_prime_UTR

Hold the cursor over a type above to highlight its positions in the sequence below.

AAGAGACCAAGAAACCGTAGCAGCTCCGTCTTCGCAGGAACTATGGCTGTCGAAGCTGACTCATCTGGAGGCTCCGATGAAGTTCATACCGACGTTCTATCGGAATCAAGACAAGCTTGCTACAAGGTGCTCTAACTCAATCACTAATTCTCTACCATTTCTGTTACATAATAATTTTTATGAGTGTTGATAAAATTTGATGCGTCTTAACAAGGCTCGCGATGCTTTTTATGCTTGTGTGGAGAAGGAATCTGATAAAAAACCTACTGAAATTGCTTCTGTTGGCCTTATTTACCCTGCCGAGTGTAAAGCTTTGAGAGCTGATTATGTCAAACTTTGCAGAGCTTCTTGGGTAAATGTCGTTTCTCGATCACTGGAGGTTACGGTAACATATTAGGTCTATTAGGTTTTGATGGTGTTTATAATTTTGTAGGTGAAGCATTTTGATAGGAAGTTTTGTCAGAACAGTAGGGTTCAAAGACTCCTAGATGACAAAGATTTGAGGAGAGGTCCGTTGATACTTCCTCAGCCTTACACTTTTAAGCCCACTAATTAAACTAAAAACAATCCCTCCGGATCAACATTGGGCGGTCAGAGTCTCATCACTATTGATATTTTGTATTTGTTGTTTTTTGCTTCTTCTTCTTTTACTCTGTATAGAAATGACTGTGGAAATAGGTTTAGTAATAATTTCCATCTTTTTACCGGACTACAAAACCTTAATCCTTCCCTTTTTGTGCATTTAGTTTTAAGGTATGATGTAGAATTAAATTTACCTTCGCCCATTGACTTAAGCTTTTGGGTGAAGGCAAATTTAATAGAATATCTAACACTCCCCCTAATAGAATACCTTTACCCACGAGCGTAAGTTTGTGTGTCAATCAGTGATTTAACATATTCAGAGCAGGTTGGTTTAGGATGTCGCGTGTTCAAACCCTTGCAATGTTATTCTCTCCCCATTTAATATTGATTTCCACTTGTTCGACTATTCTTCATATTTCAAACCCACATGTAGGGGAGTGCTAGATGATATATAATTAAATTTCCTTTTCAACCATTAGCTTAAGCTTTTAGCTCAATCGGTGATTTAAGAGGTAGTTCTAACTTCTTGCCTGACCATGATGTATTAACTAAAG

mRNA sequence

AAGAGACCAAGAAACCGTAGCAGCTCCGTCTTCGCAGGAACTATGGCTGTCGAAGCTGACTCATCTGGAGGCTCCGATGAAGTTCATACCGACGTTCTATCGGAATCAAGACAAGCTTGCTACAAGGCTCGCGATGCTTTTTATGCTTGTGTGGAGAAGGAATCTGATAAAAAACCTACTGAAATTGCTTCTGTTGGCCTTATTTACCCTGCCGAGTGTAAAGCTTTGAGAGCTGATTATGTCAAACTTTGCAGAGCTTCTTGGGTGAAGCATTTTGATAGGAAGTTTTGTCAGAACAGTAGGGTTCAAAGACTCCTAGATGACAAAGATTTGAGGAGAGGTCCGTTGATACTTCCTCAGCCTTACACTTTTAAGCCCACTAATTAAACTAAAAACAATCCCTCCGGATCAACATTGGGCGGTCAGAGTCTCATCACTATTGATATTTTGTATTTGTTGTTTTTTGCTTCTTCTTCTTTTACTCTGTATAGAAATGACTGTGGAAATAGGTTTAGTAATAATTTCCATCTTTTTACCGGACTACAAAACCTTAATCCTTCCCTTTTTGTGCATTTAGTTTTAAGGTATGATGTAGAATTAAATTTACCTTCGCCCATTGACTTAAGCTTTTGGGTGAAGGCAAATTTAATAGAATATCTAACACTCCCCCTAATAGAATACCTTTACCCACGAGCGTAAGTTTGTGTGTCAATCAGTGATTTAACATATTCAGAGCAGGTTGGTTTAGGATGTCGCGTGTTCAAACCCTTGCAATGTTATTCTCTCCCCATTTAATATTGATTTCCACTTGTTCGACTATTCTTCATATTTCAAACCCACATGTAGGGGAGTGCTAGATGATATATAATTAAATTTCCTTTTCAACCATTAGCTTAAGCTTTTAGCTCAATCGGTGATTTAAGAGGTAGTTCTAACTTCTTGCCTGACCATGATGTATTAACTAAAG

Coding sequence (CDS)

ATGGCTGTCGAAGCTGACTCATCTGGAGGCTCCGATGAAGTTCATACCGACGTTCTATCGGAATCAAGACAAGCTTGCTACAAGGCTCGCGATGCTTTTTATGCTTGTGTGGAGAAGGAATCTGATAAAAAACCTACTGAAATTGCTTCTGTTGGCCTTATTTACCCTGCCGAGTGTAAAGCTTTGAGAGCTGATTATGTCAAACTTTGCAGAGCTTCTTGGGTGAAGCATTTTGATAGGAAGTTTTGTCAGAACAGTAGGGTTCAAAGACTCCTAGATGACAAAGATTTGAGGAGAGGTCCGTTGATACTTCCTCAGCCTTACACTTTTAAGCCCACTAATTAA

Protein sequence

MAVEADSSGGSDEVHTDVLSESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECKALRADYVKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN

Homology

[Close]

BLAST of IVF0023165 vs. ExPASy TrEMBL
Match: A0A1S3B9T5 (uncharacterized protein LOC103487365 isoform X1 OS=Cucumis melo OX=3656 GN=LOC103487365 PE=4 SV=1)

HSP 1 Score: 236.9 bits (603), Expect = 4.2e-59
Identity = 114/114 (100.00%), Postives = 114/114 (100.00%), Query Frame = 0


Query: 1   MAVEADSSGGSDEVHTDVLSESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK 60
           MAVEADSSGGSDEVHTDVLSESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK
Sbjct: 1   MAVEADSSGGSDEVHTDVLSESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK 60

Query: 61  ALRADYVKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN 115
           ALRADYVKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN
Sbjct: 61  ALRADYVKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN 114

[Close]

BLAST of IVF0023165 vs. ExPASy TrEMBL
Match: A0A5A7SVN2 (Cytochrome c oxidase assembly factor 6 isoform X3 OS=Cucumis melo var. makuwa OX=1194695 GN=E5676_scaffold1369G00450 PE=4 SV=1)

HSP 1 Score: 236.9 bits (603), Expect = 4.2e-59
Identity = 114/114 (100.00%), Postives = 114/114 (100.00%), Query Frame = 0


Query: 1   MAVEADSSGGSDEVHTDVLSESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK 60
           MAVEADSSGGSDEVHTDVLSESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK
Sbjct: 1   MAVEADSSGGSDEVHTDVLSESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK 60

Query: 61  ALRADYVKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN 115
           ALRADYVKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN
Sbjct: 61  ALRADYVKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN 114

[Close]

BLAST of IVF0023165 vs. ExPASy TrEMBL
Match: A0A0A0LTX1 (Uncharacterized protein OS=Cucumis sativus OX=3659 GN=Csa_1G269850 PE=4 SV=1)

HSP 1 Score: 232.3 bits (591), Expect = 1.0e-57
Identity = 111/114 (97.37%), Postives = 112/114 (98.25%), Query Frame = 0


Query: 1   MAVEADSSGGSDEVHTDVLSESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK 60
           MA EADSSGGSDEVHTDVLSESRQACYKARDAFYAC+EKESDKKPTEIASVGLIYPAECK
Sbjct: 1   MAFEADSSGGSDEVHTDVLSESRQACYKARDAFYACMEKESDKKPTEIASVGLIYPAECK 60

Query: 61  ALRADYVKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN 115
           ALRADY KLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN
Sbjct: 61  ALRADYAKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN 114

[Close]

BLAST of IVF0023165 vs. ExPASy TrEMBL
Match: A0A6J1BZF0 (uncharacterized protein LOC111006886 OS=Momordica charantia OX=3673 GN=LOC111006886 PE=4 SV=1)

HSP 1 Score: 218.4 bits (555), Expect = 1.6e-53
Identity = 104/114 (91.23%), Postives = 110/114 (96.49%), Query Frame = 0


Query: 1   MAVEADSSGGSDEVHTDVLSESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK 60
           MAVEAD+SGG DEVH+DVL+ SRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK
Sbjct: 1   MAVEADASGGLDEVHSDVLAGSRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK 60

Query: 61  ALRADYVKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN 115
           ALRA++VKLCRASWVKHFDRKFCQNSRVQRLLDDKD RRGPL LPQPYTFKPT+
Sbjct: 61  ALRAEFVKLCRASWVKHFDRKFCQNSRVQRLLDDKDSRRGPLSLPQPYTFKPTS 114

[Close]

BLAST of IVF0023165 vs. ExPASy TrEMBL
Match: A0A6J1I7I2 (cytochrome c oxidase assembly factor 6 OS=Cucurbita maxima OX=3661 GN=LOC111471973 PE=4 SV=1)

HSP 1 Score: 216.5 bits (550), Expect = 5.9e-53
Identity = 101/114 (88.60%), Postives = 109/114 (95.61%), Query Frame = 0


Query: 1   MAVEADSSGGSDEVHTDVLSESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK 60
           MA+E D SGGS+EVHTDVL+E RQACYKARDAFYACVEKESDKKPTEIASVGL+YPAECK
Sbjct: 1   MALETDPSGGSEEVHTDVLAEFRQACYKARDAFYACVEKESDKKPTEIASVGLLYPAECK 60

Query: 61  ALRADYVKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN 115
           A RA++VKLCRASWVKHFDRKFCQNSRVQRLLDDKD RRGPL+LPQPYTFKPT+
Sbjct: 61  ASRAEFVKLCRASWVKHFDRKFCQNSRVQRLLDDKDSRRGPLVLPQPYTFKPTS 114

[Close]

BLAST of IVF0023165 vs. NCBI nr
Match: XP_008443871.1 (PREDICTED: uncharacterized protein LOC103487365 isoform X1 [Cucumis melo] >XP_008443872.1 PREDICTED: uncharacterized protein LOC103487365 isoform X1 [Cucumis melo] >KAA0035060.1 cytochrome c oxidase assembly factor 6 isoform X3 [Cucumis melo var. makuwa] >TYK03618.1 cytochrome c oxidase assembly factor 6 isoform X3 [Cucumis melo var. makuwa])

HSP 1 Score: 237 bits (605), Expect = 6.39e-79
Identity = 114/114 (100.00%), Postives = 114/114 (100.00%), Query Frame = 0


Query: 1   MAVEADSSGGSDEVHTDVLSESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK 60
           MAVEADSSGGSDEVHTDVLSESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK
Sbjct: 1   MAVEADSSGGSDEVHTDVLSESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK 60

Query: 61  ALRADYVKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN 114
           ALRADYVKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN
Sbjct: 61  ALRADYVKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN 114

[Close]

BLAST of IVF0023165 vs. NCBI nr
Match: XP_011655945.1 (uncharacterized protein LOC101212489 isoform X1 [Cucumis sativus])

HSP 1 Score: 233 bits (593), Expect = 4.33e-77
Identity = 111/114 (97.37%), Postives = 112/114 (98.25%), Query Frame = 0


Query: 1   MAVEADSSGGSDEVHTDVLSESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK 60
           MA EADSSGGSDEVHTDVLSESRQACYKARDAFYAC+EKESDKKPTEIASVGLIYPAECK
Sbjct: 1   MAFEADSSGGSDEVHTDVLSESRQACYKARDAFYACMEKESDKKPTEIASVGLIYPAECK 60

Query: 61  ALRADYVKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN 114
           ALRADY KLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN
Sbjct: 61  ALRADYAKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN 114

[Close]

BLAST of IVF0023165 vs. NCBI nr
Match: XP_038878579.1 (uncharacterized protein LOC120070767 [Benincasa hispida])

HSP 1 Score: 224 bits (570), Expect = 1.40e-73
Identity = 107/114 (93.86%), Postives = 111/114 (97.37%), Query Frame = 0


Query: 1   MAVEADSSGGSDEVHTDVLSESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK 60
           MAVEAD+SGG DEVH+DVL+ESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK
Sbjct: 1   MAVEADASGGLDEVHSDVLAESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK 60

Query: 61  ALRADYVKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN 114
           ALRA +VKLCRASWVKHFDRKFCQNSRVQRLLDDKD RRGPLILPQPYTFKPTN
Sbjct: 61  ALRAYFVKLCRASWVKHFDRKFCQNSRVQRLLDDKDSRRGPLILPQPYTFKPTN 114

[Close]

BLAST of IVF0023165 vs. NCBI nr
Match: XP_022134674.1 (uncharacterized protein LOC111006886 [Momordica charantia] >XP_022134675.1 uncharacterized protein LOC111006886 [Momordica charantia])

HSP 1 Score: 219 bits (557), Expect = 1.34e-71
Identity = 104/114 (91.23%), Postives = 110/114 (96.49%), Query Frame = 0


Query: 1   MAVEADSSGGSDEVHTDVLSESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK 60
           MAVEAD+SGG DEVH+DVL+ SRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK
Sbjct: 1   MAVEADASGGLDEVHSDVLAGSRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK 60

Query: 61  ALRADYVKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN 114
           ALRA++VKLCRASWVKHFDRKFCQNSRVQRLLDDKD RRGPL LPQPYTFKPT+
Sbjct: 61  ALRAEFVKLCRASWVKHFDRKFCQNSRVQRLLDDKDSRRGPLSLPQPYTFKPTS 114

[Close]

BLAST of IVF0023165 vs. NCBI nr
Match: XP_022973432.1 (cytochrome c oxidase assembly factor 6 [Cucurbita maxima])

HSP 1 Score: 217 bits (552), Expect = 7.78e-71
Identity = 101/114 (88.60%), Postives = 109/114 (95.61%), Query Frame = 0


Query: 1   MAVEADSSGGSDEVHTDVLSESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK 60
           MA+E D SGGS+EVHTDVL+E RQACYKARDAFYACVEKESDKKPTEIASVGL+YPAECK
Sbjct: 1   MALETDPSGGSEEVHTDVLAEFRQACYKARDAFYACVEKESDKKPTEIASVGLLYPAECK 60

Query: 61  ALRADYVKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPTN 114
           A RA++VKLCRASWVKHFDRKFCQNSRVQRLLDDKD RRGPL+LPQPYTFKPT+
Sbjct: 61  ASRAEFVKLCRASWVKHFDRKFCQNSRVQRLLDDKDSRRGPLVLPQPYTFKPTS 114

[Close]

BLAST of IVF0023165 vs. TAIR 10
Match: AT5G58005.1 (Cytochrome c oxidase, subunit Vib family protein )

HSP 1 Score: 164.9 bits (416), Expect = 3.9e-41
Identity = 74/113 (65.49%), Postives = 92/113 (81.42%), Query Frame = 0


Query: 1   MAVEADSSGGSDEVHTDVLSESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK 60
           MA++  +S   ++VH DVL ++R ACYKARDAFYAC+EKES KKPTEIA+VGL+YP EC 
Sbjct: 1   MALDTYASSNPNDVHEDVLLKARDACYKARDAFYACLEKESGKKPTEIATVGLLYPKECS 60

Query: 61  ALRADYVKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPT 114
             R  +V  CR+SWVKHFDR++C+N RVQRLLDD D R+GP+ LPQPYTFKP+
Sbjct: 61  NSRTQFVNNCRSSWVKHFDREYCRNKRVQRLLDDGDERKGPMSLPQPYTFKPS 113

[Close]

BLAST of IVF0023165 vs. TAIR 10
Match: AT5G58005.2 (Cytochrome c oxidase, subunit Vib family protein )

HSP 1 Score: 164.9 bits (416), Expect = 3.9e-41
Identity = 74/113 (65.49%), Postives = 92/113 (81.42%), Query Frame = 0


Query: 1   MAVEADSSGGSDEVHTDVLSESRQACYKARDAFYACVEKESDKKPTEIASVGLIYPAECK 60
           MA++  +S   ++VH DVL ++R ACYKARDAFYAC+EKES KKPTEIA+VGL+YP EC 
Sbjct: 1   MALDTYASSNPNDVHEDVLLKARDACYKARDAFYACLEKESGKKPTEIATVGLLYPKECS 60

Query: 61  ALRADYVKLCRASWVKHFDRKFCQNSRVQRLLDDKDLRRGPLILPQPYTFKPT 114
             R  +V  CR+SWVKHFDR++C+N RVQRLLDD D R+GP+ LPQPYTFKP+
Sbjct: 61  NSRTQFVNNCRSSWVKHFDREYCRNKRVQRLLDDGDERKGPMSLPQPYTFKPS 113

The following BLAST results are available for this feature:

BLAST of IVF0023165 vs.


Match Name	E-value	Identity	Description

BLAST of IVF0023165 vs. ExPASy TrEMBL


Match Name	E-value	Identity	Description
A0A1S3B9T5	4.2e-59	100.00	uncharacterized protein LOC103487365 isoform X1 OS=Cucumis melo OX=3656 GN=LOC10...	[more]
A0A5A7SVN2	4.2e-59	100.00	Cytochrome c oxidase assembly factor 6 isoform X3 OS=Cucumis melo var. makuwa OX...	[more]
A0A0A0LTX1	1.0e-57	97.37	Uncharacterized protein OS=Cucumis sativus OX=3659 GN=Csa_1G269850 PE=4 SV=1	[more]
A0A6J1BZF0	1.6e-53	91.23	uncharacterized protein LOC111006886 OS=Momordica charantia OX=3673 GN=LOC111006...	[more]
A0A6J1I7I2	5.9e-53	88.60	cytochrome c oxidase assembly factor 6 OS=Cucurbita maxima OX=3661 GN=LOC1114719...	[more]

BLAST of IVF0023165 vs. NCBI nr


Match Name	E-value	Identity	Description
XP_008443871.1	6.39e-79	100.00	PREDICTED: uncharacterized protein LOC103487365 isoform X1 [Cucumis melo] >XP_00...	[more]
XP_011655945.1	4.33e-77	97.37	uncharacterized protein LOC101212489 isoform X1 [Cucumis sativus]	[more]
XP_038878579.1	1.40e-73	93.86	uncharacterized protein LOC120070767 [Benincasa hispida]	[more]
XP_022134674.1	1.34e-71	91.23	uncharacterized protein LOC111006886 [Momordica charantia] >XP_022134675.1 uncha...	[more]
XP_022973432.1	7.78e-71	88.60	cytochrome c oxidase assembly factor 6 [Cucurbita maxima]	[more]

BLAST of IVF0023165 vs. TAIR 10


Match Name	E-value	Identity	Description
AT5G58005.1	3.9e-41	65.49	Cytochrome c oxidase, subunit Vib family protein	[more]
AT5G58005.2	3.9e-41	65.49	Cytochrome c oxidase, subunit Vib family protein	[more]

InterPro

Analysis Name: InterPro Annotations of Melon (IVF77) v1
Date Performed: 2021-10-25

Position :

Zoom :

x 1


IPR Term	IPR Description	Source	Source Term	Source Description	Alignment
IPR003213	Cytochrome c oxidase, subunit VIb	PFAM	PF02297	COX6B	coord: 21..92 e-value: 1.3E-18 score: 67.0
IPR036549	Cytochrome c oxidase, subunit VIb superfamily	GENE3D	1.10.10.140	Cytochrome c oxidase, subunit VIb	coord: 16..91 e-value: 1.6E-9 score: 39.5
IPR036549	Cytochrome c oxidase, subunit VIb superfamily	SUPERFAMILY	47694	Cytochrome c oxidase subunit h	coord: 22..82
None	No IPR available	PANTHER	PTHR47445:SF1	OS08G0441400 PROTEIN	coord: 1..112
None	No IPR available	PANTHER	PTHR47445	OS08G0441400 PROTEIN	coord: 1..112

Relationships

The following mRNA feature(s) are a part of this gene:


Feature Name	Unique Name	Type
IVF0023165.5	IVF0023165.5	mRNA

GO Annotation

GO Assignments

This gene is annotated with the following GO terms.

Category	Term Accession	Term Name
cellular_component	GO:0005739	mitochondrion
cellular_component	GO:0045277	respiratory chain complex IV