<?xml version="1.0" encoding="utf-8"?>
<!--Generated by DFIN XBRL Instance Document - http://www.dfinsolutions.com/ - Version R3.0 - on 11-August-2022 [09:16:21] {PM}-->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
<roleRef xlink:type="simple" xlink:href="prok-20220630.xsd#CondensedConsolidatedBalanceSheets" roleURI="http://www.businesswire.com/role/CondensedConsolidatedBalanceSheets" />
<roleRef xlink:type="simple" xlink:href="prok-20220630.xsd#CondensedConsolidatedStatementsOfOperations" roleURI="http://www.businesswire.com/role/CondensedConsolidatedStatementsOfOperations" />
<roleRef xlink:type="simple" xlink:href="prok-20220630.xsd#CondensedConsolidatedStatementsOfCashFlows" roleURI="http://www.businesswire.com/role/CondensedConsolidatedStatementsOfCashFlows" />
<calculationLink xlink:type="extended" xlink:role="http://www.businesswire.com/role/CondensedConsolidatedBalanceSheets">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="loc_us-gaap_Liabilities" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="prok-20220630.xsd#prok_DeferredUnderwritingCommissions" xlink:label="loc_PROK_DeferredUnderwritingCommissions" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities" xlink:to="loc_PROK_DeferredUnderwritingCommissions" use="optional" order="2" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities" xlink:to="loc_us-gaap_LiabilitiesCurrent" use="optional" order="3" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent" xlink:to="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" use="optional" order="4" weight="1" />
<loc xlink:type="locator" xlink:href="prok-20220630.xsd#prok_AccruedExpensesCurrent" xlink:label="loc_PROK_AccruedExpensesCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent" xlink:to="loc_PROK_AccruedExpensesCurrent" use="optional" order="5" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DueToRelatedPartiesCurrent" xlink:label="loc_us-gaap_DueToRelatedPartiesCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent" xlink:to="loc_us-gaap_DueToRelatedPartiesCurrent" use="optional" order="6" weight="1" />
<loc xlink:type="locator" xlink:href="prok-20220630.xsd#prok_NotesPayableRelatedPartyClassifiedCurrent" xlink:label="loc_PROK_NotesPayableRelatedPartyClassifiedCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent" xlink:to="loc_PROK_NotesPayableRelatedPartyClassifiedCurrent" use="optional" order="7" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="loc_us-gaap_StockholdersEquity" use="optional" order="8" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PreferredStockValue" xlink:label="loc_us-gaap_PreferredStockValue" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity" xlink:to="loc_us-gaap_PreferredStockValue" use="optional" order="9" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockValue" xlink:label="loc_us-gaap_CommonStockValue" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity" xlink:to="loc_us-gaap_CommonStockValue" use="optional" order="10" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="loc_us-gaap_AdditionalPaidInCapital" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity" xlink:to="loc_us-gaap_AdditionalPaidInCapital" use="optional" order="11" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit" use="optional" order="12" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="loc_us-gaap_CommitmentsAndContingencies" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="loc_us-gaap_CommitmentsAndContingencies" use="optional" order="13" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TemporaryEquityCarryingAmountAttributableToParent" xlink:label="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent" use="optional" order="14" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.businesswire.com/role/CondensedConsolidatedBalanceSheets">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets" xlink:to="loc_us-gaap_AssetsCurrent" use="optional" order="15" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Cash" xlink:label="loc_us-gaap_Cash" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent" xlink:to="loc_us-gaap_Cash" use="optional" order="16" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherPrepaidExpenseCurrent" xlink:label="loc_us-gaap_OtherPrepaidExpenseCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent" xlink:to="loc_us-gaap_OtherPrepaidExpenseCurrent" use="optional" order="17" weight="1" />
<loc xlink:type="locator" xlink:href="prok-20220630.xsd#prok_PrepaidInsuranceNonCurrent" xlink:label="loc_PROK_PrepaidInsuranceNonCurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets" xlink:to="loc_PROK_PrepaidInsuranceNonCurrent" use="optional" order="18" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsHeldInTrustNoncurrent" xlink:label="loc_us-gaap_AssetsHeldInTrustNoncurrent" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets" xlink:to="loc_us-gaap_AssetsHeldInTrustNoncurrent" use="optional" order="19" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.businesswire.com/role/CondensedConsolidatedStatementsOfOperations">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss" xlink:to="loc_us-gaap_OperatingIncomeLoss" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingExpenses" xlink:label="loc_us-gaap_OperatingExpenses" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss" xlink:to="loc_us-gaap_OperatingExpenses" use="optional" order="2" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherIncome" xlink:label="loc_us-gaap_OtherIncome" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss" xlink:to="loc_us-gaap_OtherIncome" use="optional" order="3" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentIncomeInterest" xlink:label="loc_us-gaap_InvestmentIncomeInterest" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OtherIncome" xlink:to="loc_us-gaap_InvestmentIncomeInterest" use="optional" order="4" weight="1" />
</calculationLink>
<calculationLink xlink:type="extended" xlink:role="http://www.businesswire.com/role/CondensedConsolidatedStatementsOfCashFlows">
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" use="optional" order="1" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt" xlink:label="loc_us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt" use="optional" order="2" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProceedsFromNotesPayable" xlink:label="loc_us-gaap_ProceedsFromNotesPayable" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaap_ProceedsFromNotesPayable" use="optional" order="3" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsOfStockIssuanceCosts" xlink:label="loc_us-gaap_PaymentsOfStockIssuanceCosts" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaap_PaymentsOfStockIssuanceCosts" use="optional" order="4" weight="-1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" use="optional" order="5" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInPrepaidExpense" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidExpense" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidExpense" use="optional" order="6" weight="-1" />
<loc xlink:type="locator" xlink:href="prok-20220630.xsd#prok_IncreaseDecreaseInAdvancesFromRelatedParty" xlink:label="loc_PROK_IncreaseDecreaseInAdvancesFromRelatedParty" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_PROK_IncreaseDecreaseInAdvancesFromRelatedParty" use="optional" order="7" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" use="optional" order="8" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentIncomeInterest" xlink:label="loc_us-gaap_InvestmentIncomeInterest" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaap_InvestmentIncomeInterest" use="optional" order="9" weight="-1" />
<loc xlink:type="locator" xlink:href="prok-20220630.xsd#prok_FormationCostsPaidBySponsorInExchangeForIssuanceOfOrdinaryShares" xlink:label="loc_PROK_FormationCostsPaidBySponsorInExchangeForIssuanceOfOrdinaryShares" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_PROK_FormationCostsPaidBySponsorInExchangeForIssuanceOfOrdinaryShares" use="optional" order="10" weight="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss" />
<calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaap_NetIncomeLoss" use="optional" order="11" weight="1" />
</calculationLink>
</linkbase>
