View source for Protamine

{{cs1 config|name-list-style=vanc}}
{{infobox protein
|Name=[[PRM1|Protamine 1]]
|caption=
|image=
|width=
|HGNCid=9447
|Symbol=[[PRM1]]
|AltSymbols=
|EntrezGene=5619
|OMIM=182880
|RefSeq=NM_002761
|UniProt=P04553
|PDB=
|ECnumber=
|Chromosome=16
|Arm=p
|Band=13.13
|LocusSupplementaryData=
}}
{{infobox protein
|Name=[[PRM2|Protamine 2]]
|caption=
|image=
|width=
|HGNCid=9448
|Symbol=[[PRM2]]
|AltSymbols=
|EntrezGene=5620
|OMIM=182890
|RefSeq=NM_002762
|UniProt=P04554
|PDB=
|ECnumber=
|Chromosome=16
|Arm=p
|Band=13.13
|LocusSupplementaryData=
}}
'''Protamines''' are small, [[arginine]]-rich, [[cell nucleus|nuclear]] [[proteins]] that replace [[histones]] late in the [[haploid]] phase of [[spermatogenesis]] and are believed essential for [[sperm]] head condensation and [[DNA]] stabilization. They may allow for denser packaging of DNA in the [[spermatozoon]] than histones, but they must be decompressed before the genetic data can be used for protein synthesis. However, part of the sperm's genome is packaged by histones (10-15% in humans and other primates) thought to bind genes that are essential for early embryonic development.<ref name="Balhorn_2007">{{cite journal | vauthors = Balhorn R | title = The protamine family of sperm nuclear proteins | journal = Genome Biology | volume = 8 | issue = 9 | pages = 227 | year = 2007 | pmid = 17903313 | pmc = 2375014 | doi = 10.1186/gb-2007-8-9-227 | doi-access = free }}</ref>

Protamine and '''protamine-like''' (PL) proteins are collectively known as the '''sperm-specific nuclear basic proteins''' (SNBPs). The PL proteins are intermediate in structure between protamine and [[Histone H1]]. The C-terminal domain of PL could be the precursor of vertebrate protamine.<ref name=pmid19708021>{{cite journal | vauthors = Eirín-López JM, Ausió J | title = Origin and evolution of chromosomal sperm proteins | journal = BioEssays | volume = 31 | issue = 10 | pages = 1062–70 | date = October 2009 | pmid = 19708021 | doi = 10.1002/bies.200900050 | s2cid = 17131119 }}</ref>

== Spermatogenesis ==
[[File:Dynamic alterations in the paternal epigenetic landscape following fertilization F1.jpg|thumb|300px|left|Alterations to the epigenome post-fertilization. The upper part of the image shows replacement of protamines with histones in paternal pronucleus shortly after fertilization. DNA packaged with protamines forms toroid-shaped structures, shown at the top left corner of the image.<ref name=":3">{{cite journal | vauthors = Jenkins TG, Carrell DT | title = Dynamic alterations in the paternal epigenetic landscape following fertilization | language = English | journal = Frontiers in Genetics | volume = 3 | pages = 143 | date = 2012 | pmid = 23024648 | pmc = 3442791 | doi = 10.3389/fgene.2012.00143 | doi-access = free }}</ref>]]During the formation of sperm, protamine binds to the phosphate backbone of DNA using the arginine-rich domain as an anchor. DNA is then folded into a [[toroid]], an O-shaped structure, although the mechanism is not known. A sperm cell can contain up to 50,000 toroid-shaped structures in its nucleus with each toroid containing about 50 kilobases.<ref>{{cite journal | vauthors = Brewer LR, Corzett M, Balhorn R | title = Protamine-induced condensation and decondensation of the same DNA molecule | journal = Science | volume = 286 | issue = 5437 | pages = 120–3 | date = October 1999 | pmid = 10506559 | doi = 10.1126/science.286.5437.120 | url = https://zenodo.org/record/1231163 }}</ref> Before the toroid is formed, histones are removed from the DNA by [[transition nuclear protein]]s, so that protamine can condense it. The effects of this change are 1) an increase in sperm hydrodynamics for better flow through liquids by reducing the head size 2) decrease in the occurrence of DNA damage 3) removal of the epigenetic markers that occur with histone modifications.<ref>{{cite journal | vauthors = Woop M | title = Optimizing Tethered Particle Motion to Measure DNA Compaction by Protamine | journal = Biophysical Journal |volume=108 | issue = 2 | page = 393a | date=January 2015 | doi=10.1016/j.bpj.2014.11.2156| bibcode = 2015BpJ...108..393W | doi-access = free }}</ref>

The structure of the sperm head is also related to protamine levels. The ratio of protamine 2 to protamine 1 and transition nuclear proteins has been found to change the sperm head shape in various species of mice, by altering the expression of protamine 2 via mutations in its promoter region. A decrease in the ratio has been found to increase the competitive ability of sperm in [[Mus (genus)|Mus]] species. However, further testing is required to determine how this ratio influences the shape of the head and whether monogamy influences this selection. In humans, studies show that men who have unbalanced Prm1/Prm2 are subfertile or infertile.<ref>{{cite journal | vauthors = Lüke L, Campbell P, Varea Sánchez M, Nachman MW, Roldan ER | title = Sexual selection on protamine and transition nuclear protein expression in mouse species | journal = Proceedings. Biological Sciences | volume = 281 | issue = 1783 | pages = 20133359 | date = May 2014 | pmid = 24671975 | pmc = 3996607 | doi = 10.1098/rspb.2013.3359 }}</ref> Protamine 2 is encoded as a longer protein that needs its N-terminal cleaved before becoming functional. Human and chimp protamine has undergone rapid evolution.<ref>{{cite journal | vauthors = Wyckoff GJ, Wang W, Wu CI | title = Rapid evolution of male reproductive genes in the descent of man | journal = Nature | volume = 403 | issue = 6767 | pages = 304–9 | date = January 2000 | pmid = 10659848 | doi = 10.1038/35002070 | s2cid = 3136139 | bibcode = 2000Natur.403..304W }}</ref>
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== Medical uses ==
{{see also|Protamine sulfate}}
When mixed with [[insulin]], protamines slow down the onset and increase the duration of insulin action (see [[NPH insulin]]).<ref name="pmid21668337">{{cite journal | vauthors = Owens DR | title = Insulin preparations with prolonged effect | journal = Diabetes Technology & Therapeutics | volume = 13 | pages = S5-14 | date = June 2011 | issue = Suppl 1 | pmid = 21668337 | doi = 10.1089/dia.2011.0068 | doi-access =  }}</ref>

Protamine is used in cardiac surgery, vascular surgery, and interventional radiology procedures to neutralize the anti-clotting effects of [[heparin]]. Adverse effects include increased pulmonary artery pressure and decrease peripheral blood pressure, myocardial oxygen consumption, cardiac output, and heart rate.<ref name="pmid10596998">{{cite journal | vauthors = Carr JA, Silverman N | title = The heparin-protamine interaction. A review | journal = The Journal of Cardiovascular Surgery | volume = 40 | issue = 5 | pages = 659–66 | date = October 1999 | pmid = 10596998 }}</ref>

[[Protamine sulfate]] is an antidote for [[heparin]] overdose, but severe allergy may occur.<ref name="pmid2857186">{{cite journal | vauthors = Weiler JM, Freiman P, Sharath MD, Metzger WJ, Smith JM, Richerson HB, Ballas ZK, Halverson PC, Shulan DJ, Matsuo S | display-authors = 6 | title = Serious adverse reactions to protamine sulfate: are alternatives needed? | journal = The Journal of Allergy and Clinical Immunology | volume = 75 | issue = 2 | pages = 297–303 | date = February 1985 | pmid = 2857186 | doi = 10.1016/0091-6749(85)90061-2 | doi-access = free }}</ref>  A chain shortened version of protamine also acts as a potent heparin antagonist, but with markedly reduced [[antigenicity]]. It was initially produced as a mixture made by [[thermolysin]] digestion of protamine,<ref name="pmid10926141">{{cite journal | vauthors = Byun Y, Chang LC, Lee LM, Han IS, Singh VK, Yang VC | title = Low molecular weight protamine: a potent but nontoxic antagonist to heparin/low molecular weight protamine | journal = ASAIO Journal | volume = 46 | issue = 4 | pages = 435–9 | year = 2000 | pmid = 10926141 | doi = 10.1097/00002480-200007000-00013 | s2cid = 13106365 | doi-access = free }}</ref> but the actual effective peptide portion <code>VSRRRRRRGGRRRR</code> has since been isolated.<ref>{{cite journal | vauthors = He H, Ye J, Liu E, Liang Q, Liu Q, Yang VC | title = Low molecular weight protamine (LMWP): a nontoxic protamine substitute and an effective cell-penetrating peptide | journal = Journal of Controlled Release | volume = 193 | pages = 63–73 | date = November 2014 | pmid = 24943246 | doi = 10.1016/j.jconrel.2014.05.056 }}</ref> An analogue of this peptide has also been produced.<ref>{{cite journal | vauthors = Chang LC, Lee HF, Yang Z, Yang VC | title = Low molecular weight protamine (LMWP) as nontoxic heparin/low molecular weight heparin antidote (I): preparation and characterization | journal = AAPS PharmSci | volume = 3 | issue = 3 | pages = 7–14 | date = 1 September 2001 | pmid = 11741268 | pmc = 2751012 | doi = 10.1208/ps030317 }}</ref>

In gene therapy, [[protamine sulfate]]'s ability to condense plasmid DNA along with its approval by the U.S. [[Food and Drug Administration]] (FDA) have made it an appealing candidate to increase transduction rates by both viral<ref name="Cornetta 1989">{{cite journal | vauthors = Cornetta K, Anderson WF | title = Protamine sulfate as an effective alternative to polybrene in retroviral-mediated gene-transfer: implications for human gene therapy | journal = Journal of Virological Methods | volume = 23 | issue = 2 | pages = 187–94 | date = February 1989 | pmid = 2786000 | doi = 10.1016/0166-0934(89)90132-8 | url = https://zenodo.org/record/1258363 }}</ref> and nonviral (e.g. utilizing cationic liposomes)<ref name="Sorgi 1997">{{cite journal | vauthors = Sorgi FL, Bhattacharya S, Huang L | title = Protamine sulfate enhances lipid-mediated gene transfer | journal = Gene Therapy | volume = 4 | issue = 9 | pages = 961–8 | date = September 1997 | pmid = 9349433 | doi = 10.1038/sj.gt.3300484 | s2cid = 22101764 | doi-access = free }}</ref> mediated delivery mechanisms.

Protamine may be used as a drug to prevent obesity. Protamine has been shown to deter increases in body weight and [[low-density lipoprotein]] in high-fat diet rats. This effect occurs through the inhibition of [[lipase]] activity, an enzyme responsible for [[triacylglycerol]] digestion and absorption, resulting in a decrease in the absorption of dietary fat. No liver damage was found when the rats were treated with protamine. However, emulsification of long-chain fatty acids for digestion and absorption in the small intestine is less constant in humans than rats, which will vary the effectiveness of protamine as a drug. Furthermore, human peptidases may degrade protamine at different rates, thus further tests are required to determine protamine's ability to prevent obesity in humans.<ref>{{cite journal | vauthors = Duarte-Vázquez MA, García-Padilla S, Olvera-Ochoa L, González-Romero KE, Acosta-Iñiguez J, De la Cruz-Cordero R, Rosado JL | title = Effect of protamine in obesity induced by high-fat diets in rats | journal = International Journal of Obesity | volume = 33 | issue = 6 | pages = 687–92 | date = June 2009 | pmid = 19434066 | doi = 10.1038/ijo.2009.78 | s2cid = 22589323 | doi-access =  }}</ref>

== Species distribution and isoforms ==
Mice, humans<ref name="Balhorn_2007"/> and certain fish have two or more different protamines, whereas the sperm of bull and boar,<ref name="pmid2320417">{{cite journal | vauthors = Maier WM, Nussbaum G, Domenjoud L, Klemm U, Engel W | title = The lack of protamine 2 (P2) in boar and bull spermatozoa is due to mutations within the P2 gene | journal = Nucleic Acids Research | volume = 18 | issue = 5 | pages = 1249–54 | date = March 1990 | pmid = 2320417 | pmc = 330441 | doi = 10.1093/nar/18.5.1249 }}</ref> have one form of protamine due to a mutation in the PRM2 gene. In the rat, although the gene for PRM2 is present, expression of this protein is extremely small because of limited transcription due to an inefficient promoter in addition to altered processing of the mRNA transcript.<ref>{{cite journal | vauthors = Bunick D, Balhorn R, Stanker LH, Hecht NB | title = Expression of the rat protamine 2 gene is suppressed at the level of transcription and translation | journal = Experimental Cell Research | volume = 188 | issue = 1 | pages = 147–52 | date = May 1990 | pmid = 2328773 | doi = 10.1016/0014-4827(90)90290-q }}</ref>

=== Mammals ===
The 2 human protamines are denoted [[PRM1]] and [[PRM2]].
In mice and humans, PRM1, PRM2, and [[TNP2]] are co-located in a conserved [[gene cluster]].<ref>{{cite journal | vauthors = Wykes SM, Krawetz SA | title = Conservation of the PRM1 → PRM2 → TNP2 domain | journal = DNA Sequence | volume = 14 | issue = 5 | pages = 359–67 | date = October 2003 | pmid = 14756422 | doi = 10.1080/10425170310001599453 | s2cid = 37737173 }}</ref>

[[Eutherian]] mammals generally have both PRM1 and PRM2. Metatherians on the other hand only have a homolog to P1.<ref name="entropy2"/>

=== Fish ===
Examples of protamines from fish are:
* salmine and [[protamine sulfate]] from [[salmon]]
* clupeine from [[herring]] sperm (''Clupea'')
* iridine from [[rainbow trout]]
* thinnine from [[tunafish]] (''Thunnus'')
* stelline from starry sturgeon (''[[Sturgeon|Acipenser stellatus]]'')
* scylliorhinine from [[Squaliformes|dogfish]] (''Scylliorhinus'')

Fish protamine are generally shorter than that of mammals, with a higher amount of arginine.<ref name="entropy2"/>

== Sequence ==
{{Infobox protein family |Symbol = Protamine_P1 |Name = Protamine P1 |Pfam = PF00260 |InterPro = IPR000221 |PROSITE = PDOC00047 |PDB = }}
{{Infobox protein family |Symbol = Protamine_P2 |Name = Protamine P2 |Pfam = PF00841 |InterPro = IPR000492 |PDB = }}
[[File:Protamine-DNA model.png|thumb|262x262px|Theoretical model of two adjacent salmon protamine molecules (blue) wrapped around and bound within the major groove the DNA helix (white). Protamine binding neutralizes the phosphodiester backbone of DNA, causing it to coil into toroidal structures.<ref>{{cite journal | vauthors = Balhorn R | title = The protamine family of sperm nuclear proteins | journal = Genome Biology | volume = 8 | issue = 9 | pages = 227 | date = 2007-09-26 | pmid = 17903313 | pmc = 2375014 | doi = 10.1186/gb-2007-8-9-227 | doi-access = free }}</ref>]]
The primary structure of protamine P1, the protamine used for packaging DNA in sperm cells, in placental mammals is usually 49 or 50 amino acids long. This sequence is divided into three separate domains: an arginine-rich domain for DNA binding flanked by shorter peptide sequences containing mostly cysteine residues. The arginine-rich domain consists of 3-11 arginine residues and is conserved between fish protamine and mammalian protamine 1 sequences at about 60-80% sequence identity.<ref name="Balhorn_2007"/>

== Structure ==
After translation, the protamine P1 structure is immediately phosphorylated at all three of the above-mentioned domains. Another round of phosphorylation occurs when the sperm enters the egg, but the function of these phosphorylations is uncertain.<ref name="Balhorn_2007" />

The exact secondary and tertiary structure of protamine is not known with certainty, but several proposals have been published since the 1970s.<ref>{{cite journal | vauthors = Warrant RW, Kim SH | title = alpha-Helix-double helix interaction shown in the structure of a protamine-transfer RNA complex and a nucleoprotamine model | journal = Nature | volume = 271 | issue = 5641 | pages = 130–5 | date = January 1978 | pmid = 622153 | doi = 10.1038/271130a0 | bibcode = 1978Natur.271..130W | s2cid = 4172929 }}</ref><ref name=":0">{{cite journal | vauthors = Hud NV, Milanovich FP, Balhorn R | title = Evidence of novel secondary structure in DNA-bound protamine is revealed by Raman spectroscopy | journal = Biochemistry | volume = 33 | issue = 24 | pages = 7528–35 | date = June 1994 | pmid = 8011618 | doi = 10.1021/bi00190a005 }}</ref><ref name="Balhorn_2007" /><ref name="pmid15452126">{{cite journal | vauthors = Martins RP, Ostermeier GC, Krawetz SA | title = Nuclear matrix interactions at the human protamine domain: a working model of potentiation | journal = The Journal of Biological Chemistry | volume = 279 | issue = 50 | pages = 51862–8 | date = December 2004 | pmid = 15452126 | doi = 10.1074/jbc.M409415200 | doi-access = free }}</ref><ref name="pmid14990583">{{cite journal | vauthors = Vilfan ID, Conwell CC, Hud NV | title = Formation of native-like mammalian sperm cell chromatin with folded bull protamine | journal = The Journal of Biological Chemistry | volume = 279 | issue = 19 | pages = 20088–95 | date = May 2004 | pmid = 14990583 | doi = 10.1074/jbc.M312777200 | doi-access = free }}</ref><ref name="entropy2">{{cite journal | vauthors = Powell CD, Kirchoff DC, DeRouchey JE, Moseley HN | title = Entropy based analysis of vertebrate sperm protamines sequences: evidence of potential dityrosine and cysteine-tyrosine cross-linking in sperm protamines | journal = BMC Genomics | volume = 21 | issue = 1 | pages = 277 | date = April 2020 | pmid = 32245406 | pmc = 7126135 | doi = 10.1186/s12864-020-6681-2 | doi-access = free }}</ref><ref name=":2">{{cite journal | vauthors = Ukogu OA, Smith AD, Devenica LM, Bediako H, McMillan RB, Ma Y, Balaji A, Schwab RD, Anwar S, Dasgupta M, Carter AR | display-authors = 6 | title = Protamine loops DNA in multiple steps | journal = Nucleic Acids Research | volume = 48 | issue = 11 | pages = 6108–6119 | date = June 2020 | pmid = 32392345 | doi = 10.1093/NAR/GKAA365 | pmc = 7293030 }}</ref> The broad consensus is that protamine forms beta strand structures that then crosslink through [[disulfide bonds]] (and potentially [[dityrosine]] and cysteine-tyrosine bonds).<ref name="pmid14990583" /><ref name="entropy2"/> When protamine P1 binds to DNA, cysteine from the amino terminal of one protamine P1 forms [[disulfide bonds]] with the cysteine from the carboxy-terminal of another protamine P1. By neutralizing the backbone charge protamine enables the DNA to more tightly coil.<ref name=":3" /><ref name=":2" /> The disulfide bonds function to prevent the dissociation of protamine P1 from DNA until the bonds are reduced when the sperm enters the egg.<ref name="Balhorn_2007" /> These long protamine polymers may then wrap around the DNA within the major groove.<ref name="Balhorn_2007" /><ref name=":0" />
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== See also ==
* [[Epigenetics]]
* [[Chromosome]]

== References ==
{{Reflist|32em}}

== External links ==
* {{MeshName|Protamines}}
* {{ATC|V03|AB14}}

{{Antidotes}}

[[Category:DNA-binding proteins]]